The correct answer is 72.

Solution:

Considering the given number pattern.

Here, the numbers are decreasing.
So, to find the missing number, we first find the rule.

Note that:
84 – 4 = 80
80 – 4 = 76
76 – 4 = 72
72 – 4 = 68

So, the rule is "subtract 4".

Then, the missing number is 72.