Well did you try the two braces (without the comments of course)? Did they work?
//but what about this? Do I need a { here?
This is why it is usually recommend to always use braces with all control statements, even when not technically required, at least until you are much more familiar with the language.
For that you'll need to either have an array big enough to hold all of your choices, or individual variables for each choice. Then you need to keep track of the correct answers for each choice.
The srand() function only needs to be called once to seed the random number generator. Calling srand() multiple times in a loop using time(0) as the seed will likely lead to reseeding the random number generator with the same seed multiple times which will usually cause the random numbers to "restart" with the same sequence. Remember that time(0) only changes once every second, and using the same seed with srand() will cause the random number generator to restart at the same point in the sequence, causing repeats of the random numbers.