My (21F) best friend (22F) is angry I didn't chose her for a holiday.

I(21F) won a competition for a week's trip to a luxury beach resort with a friend. I also have 3 close friends (all 22F). One hates getting tan (carries around a shade umbrella and everything), and one hates the beach. They are well aware I'm not chosing them, and they couldn't care less.
The last friend, C, loves concept of the beach and sorely wishes she lives a celebrity lifestyle which is heavily influenced by following social media influencers on Instagram. But I can't stand overnight trips with her, let alone a week of sharing the same room. I went on a roadtrip with her last summer and she cut the trip short after two days because she was bored and demanded we turn the car around. She's the kind of friend that's great in small doses, but she starts complaining about everything after a while. She's also very self-conscious, so when we do go to the beach, she never takes off her shirt and pants, and she claims fatigue after an hour and we have to go home. She knows this, and she always makes jokes about how she acts when she goes out with people. Which is why I didn't chose her, because I knew in my bones that she would be hyped for the first day, but stay in the hotel room or indoors for the rest of the trip.
When I told my friends tonight that I chose my sister (23F) because she was getting married next year to go with me, C lost her mind. She screamed at me for not chosing her, that I always hated her, and that I knew she loved beaches and resorts. I was honestly shocked and my other friends were too. C left the bar crying. I'm trying to think of how to explain to her my choice.
Tl;dr Friend is furious I didn't chose her for a resort trip. How to explain my decision to her without hurting her feelings?
Edit: I guess I should have worded it more clearly.
We love each other to bits. We spend time together very often - but like I mentioned, for short bursts for time like a shopping trip or a dinner date. We've been friends since primary school, however she tends to be a lot more of a homebody. In my explanation I talked more about why I wouldn't pick her for the trip- I didn't mention why I'm friends in the first place because that wasnt really relevant. She's very funny, loyal and she always makes me smile. We cook together a lot, and our time together usually revolves around one singular activity. For example, we have a baking night - I go over to hers, we make a cake, we eat the cake, I go home. We also spend a lot of time online together, where she is more comfortable in her own space at home, or watching movies in my room. It's just how our relationship works.
She's very sensitive, and she tends to think the world is against her - girls walking by laughing would make her think they were laughing about her, etc. I want to be clear that I want to make her feel better - a lot of people are commenting that I shouldn't be friends with her anymore, but I do sincerely want to make her understand why I didn't choose her for the trip without making her feel worse.
Since I've posted this, one of my friends has reached out and said that C thought she was a shoe-in for the position, and that she had already started talking about her trip to Byron Bay to other mutual friends, and her reaction may be in fact embarrassment. I'm now even more unsure of how to approach this situation.
My sister has been so excited, because after her wedding, she's moving to a different country where her fiance lives, and I truly want to spend time with her. So my choice isn't going to be changing.


Source.