Xavior took a total of 124 quarters and dimes to trade in for cash at the bank. He got exactly $25 back. How many quarters did he have?

A. 
40

B. 
62

C. 
84

D. 
100

Let's assume that Xavior had q quarters and d dimes.

The total number of coins he had is given by the equation q + d = 124.

The total value of the coins in dollars is given by the equation 0.25q + 0.10d = 25.

We can multiply the second equation by 100 to eliminate the decimals:
25q + 10d = 2500.

Now we can solve the system of equations:

q + d = 124 (equation 1)
25q + 10d = 2500 (equation 2)

From equation 1, we can solve for d: d = 124 - q.

Now, substitute this value of d into equation 2:
25q + 10(124 - q) = 2500
25q + 1240 - 10q = 2500
15q + 1240 = 2500
15q = 1260
q = 84

Therefore, Xavior had 84 quarters.

The correct answer is C. 84.