To measure 5 inches using a ruler marked in 1-inch units, you would need to find two values that have a difference of 5 inches.
The difference between:
A: 3 1/2 in. and 6 1/2 in. is 6 1/2 - 3 1/2 = 3 inches.
B: 3 3/4 in. and 6 1/4 in. is 6 1/4 - 3 3/4 = 2 1/2 inches.
C: 4 1/2 in. and 5 1/2 in. is 5 1/2 - 4 1/2 = 1 inch.
D: 4 3/4 in. and 5 1/4 in. is 5 1/4 - 4 3/4 = 1/2 inch.
So, the only pair of values that have a difference of 5 inches is option A: 3 1/2 in. and 6 1/2 in.