n is the least natural number that must be subtracted from 23 so that the resulting number is a perfect square, the value of n is:

1. 7

2. 2

3. 5

4. -7

Since 4² < 23 < 5²,

The least number that must be subtracted from 23 to make the resulting number a perfect square = 23 - 4² = 23 - 16 = 7.

Hence, option 1 is the correct option.