Answer:
D. 2
Step-by-step explanation:
The skydiver will reach terminal velocity when gravity = air resistance. When this occurs, he/she will no longer accelerate and his/her speed will be constant.
Once the skydiver opens the parachute, his/her speed will decrease suddenly, and again the air resistance increases due to the parachute's large area. Eventually, gravity will equal air resistance again and terminal velocity will be reached for the second time.
Even though the speeds are different, the first terminal velocity is much higher than the second one, this question refers to how many times terminal velocity is reached, not how many times the skydiver accelerates.