What muscle is letter B showing in the diagram below?

rectus femoris

aloha! my name is zalgo and i am here to you out on this glorious day. i am very sorry to here about your relationship with your parents, but i have just the solution for you! in most cases, people can not just abruptly stop completely, you have to slowly take yourself away from them. and the best thing to do is to also show your parents that you are honestly trying your hardest to stop drinking and smoking! not only can people also not just stop suddenly, but it can cause health problems. you could have seizures and all sorts of bad things happen to you, and i am most definitely sure that your parents don't want to hear about their beloved child in the hospital. i had to hear about my little brother in the hospital and i was in shambles, so imagine your parents hearing about

i hope this advice ! : d

"stay and stay proud! " - zalgo