What is the next number in the series of numbers below? Replace the question mark with a number and select the correct answer from the four choices available. 31, 37, 41, 47, (?)

You have to find the missing number in a sequence of numbers. You will work out the relationship between the first two numbers, then between the second and third and so on.
 

Example: What is the next number in the series of numbers below? Replace the question mark with a number and select the correct answer from the four choices available.
2, 4, 6, 8, 10 (?)

12
11
14
2

The correct answer is 12 because the numbers are going up by 2 each time. 10 + 2 = 12.