How did they ended up having sex?

Choices:
A. At the girl's request.
B. After the girl said she couldn't sleep.
C. not enough information
D. After he took the floor to sleep.
At the girl's request.
I referenced this in my answer to Why do guys pretend they don't understand when the girl they like gives them all hints of liking them too?
While attending my MOS AIT in the US Army (good lord, was that 25 years ago???), a few of us had a hotel party. It didn’t get too crazy as it was mainly to get off post. If I remember right, after some folks left, there was one couple, a couple girls (maybe 3?), and myself who stayed over. I had known them all for a month or so and had spent a ton of time hanging out at the barracks or around the school area. The couple took one bed, the girls took the other, and I took the floor at the foot of the girls’ bed.
About the time everyone started to nod off, one of the girls woke me, asking if I would share the blanket, as the bed was too crowded. She and I had both recently gotten engaged to people two plane flights away and had been nothing more than friends previously - with no hint of anything else… I thought nothing of it and said sure.
After a few minutes, she said she couldn’t sleep and asked if she could snuggle up a little. I thought nothing of it and said sure. I started to think… hunh… this is peculiar…
After a few more minutes, she asked if I minded if we kissed a little. At that point, I started to get the idea… but that was as far as I thought anything was going to happen as I thought, hunh, OK, maybe she misses her fiance. I know I do.
Then we progressed to (very quiet) sex at her request. As far as we knew, everyone else in the room was asleep - at least they never hinted at knowing.
We dated another month or two while we were both there.
I was so clueless as to how she felt and it took FAR too long to figure out what was happening.