Find the missing number?

In the following question, select the missing number from the given responses.

Find the missing number.

Find the missing number?

A series is given with one term missing. Select the correct alternative from the given ones that will complete the series.
I, L, O, R, ?

Directions : Find the missing number from the given responses in each of the following questions . 

Find the missing number from the given alternatives.

In the given figure select the number that can replace the question mark (?).