Answer:
16
Explanation:
Given
A coin
--- Number of flips

Required
Which can't be the value of x
From the question, we understand that the coin was flipped 7 times.
This means that, the highest occurrence of head is:

And the list is:

So, the range of x is:

In the above range, only (16) is out of range.
Hence:
--- Number of heads can't be 16