Given a math problem with context and a question and 5 answer choices, the task is to provide the correct answer choice based on the problem. You must choose one of the given answer choices by letter: a, b, c, d, or e; anything else is invalid.

Problem: what is the probability of getting a queen or spade from a set of cards ?
Options: a. 3 / 13, b. 4 / 13, c. 5 / 13, d. 6 / 13, e. 7 / 13
b

Problem: a fruit - salad mixture consists of apples, peaches, and grapes in the ratio 6: 5: 4, respectively, by weight. if 60 pounds of the mixture is prepared, the mixture includes how many more pounds of apples than grapes ?
Options: a. 15, b. 12, c. 8, d. 6, e. 4
c

Problem: if b is the center of the circle in the figure above and the area of the shaded region is 16 π, what is the length of arc adc ?
Options: ['a. 4', 'b. 4 π', 'c. 16', 'd. 8 π', 'e. 16']

b