Which characteristic is associated with adolescence?
a. wondering if life was well spent
b. understanding the difference between the id and the ego
c. increased social pressures
d. awareness of mortality

I think that the best answer is the following one: c. Increased social pressures. This is fore example seen in peer pressure. 

Adolescence is not yet the time for existential fears and increased awareness - this usually happens later, for example during the mid-life crisis.