Consider the Following Scenario When Answering the Following Questions

Consider the following scenario when answering the following questions:
Suppose that in an experimental setting,100 students are asked to choose between Gamble A and Gamble B,where:
Gamble A: The student will receive $50 with a 70 percent probability and $100 with a 30 percent probability.
Gamble B: The student will receive $50 with a 50 percent probability,$200 with a 25 percent probability,and $0 (nothing) with a 25 percent probability.
-Which of the following shows the correct formula for the expected value (EV) of Gamble A?

A) EV = 0.7 * ($50) + 0.3 * ($100)
B) EV = 0.5 *($50) + 0.3 * ($100)
C) EV = 0.7 * ($50) + 0.5 * ($100)
D) EV = 0.5 *($50) + 0.5 *($100)
E) EV = 0.1 *($50) + 0.2 * ($100)