Which of the following is not a mathematical function?

The correct answer is Option (3) → OR 

OR → A logical function, not mathematical, as it checks whether any given conditions are TRUE.

ROUNDUP (number, num_digits) which rounds a number up, away from 0 (zero).

COUNT: This function counts the number of cells that contain numbers and counts numbers within the list of arguments. COUNT is use to get the number of the entries in a number field (including date also) i.e. in a range or array of numbers

SUMIF is the function which adds the cells as per given specified criteria.