In a class of 30 students, A is ranked 10th from the top. What is A's rank from the bottom?

B. 21ST

In a race of 50 runners, if Mark is in 15th position and he swaps places with the runner in 30th position, what will be Mark's new rank from the top?

C. 16

Alice is ranked 5th from the top and 26th from the bottom in a competition. How many participants are there in total?

B. 31

In the sequence 2, 4, 6, 8, 10, 12, how many times does the number 8 occur?

A. 1

If Sarah is ranked 5th from the top and 10th from the bottom in a competition, how many competitors are there?

B. 15