In a pattern of letters: X, Y, Z, A, B, ?, D. What is the missing letter?

A. C

In the sequence 5, 10, 15, 20, 25, 30, how many times does the number 15 occur?

A. 1

If P - Q means P is the sister of Q, Q + R means Q is the mother of R, and R * S means R is the son of S, what is the relationship of P to S?

B. AUNT

There are four animals: a dog, a cat, a rabbit, and a turtle. The dog is faster than the cat but slower than the rabbit. The turtle is the slowest of all. Which animal is the fastest?

C. RABBIT

If the word 'CAT' is coded as 3120, what is the code for the word 'DOG'?

A. 4157