1)A, shelve, shelve b, and press enter; Arrive; Let the car drive into c and discuss; Discuss, complete, realize, implement and execute.

So choose C.

Be to do is an upcoming action in the future tense. Passengers are not allowed to stick their heads out to avoid injury.

So choose d

3) People (generally) think that … "People think that …" is a fixed collocation.

So choose B.

I hope I can help you and wish you success in the exam!