Correct Answer - Option 4 : 3
COUNT function in Excel:
The COUNT function counts the number of cells that contain numbers and counts numbers within the list of arguments. Use the COUNT function to get the number of entries in a number field that is in a range or array of numbers.
COUNT(value1, [value2], ...)
The contents of cells A1, A2, B1, and B2 are 0, 0, a, and 0 respectively.
COUNT (A1: B2)= 3 because there are three numeric values in the cell.
Hence the correct answer is 3.