The smallest natural number by which should 175 be divided to get a perfect square number is:

1. 5

2. 7

3. 15

4. none of the above

Finding prime factors of 175

175 = (5 x 5) x 7

Since the prime factor 7 is not in pair.

The given number should be divided by 7.

Hence, option 2 is the correct option.