To find the least number that must be subtracted from 5607 to get a perfect square, we need to consider the concept of perfect squares and their properties.

A perfect square is a number that can be expressed as the square of an integer. For example, 4, 9, 16, 25, etc. are perfect squares because they can be expressed as the square of 2, 3, 4, 5, etc.

In order to determine the least number that must be subtracted from 5607 to obtain a perfect square, we can start by finding the square root of 5607 and then subtracting the next smallest integer from it.

1. Finding the square root of 5607:
The square root of 5607 is approximately 74.827.

2. Subtracting the next smallest integer:
The next smallest integer less than 74.827 is 74.

3. Subtracting 74 from 5607:
5607 - 74 = 5533.

Now, we need to check if 5533 is a perfect square by finding its square root.

1. Finding the square root of 5533:
The square root of 5533 is approximately 74.383.

Since the square root of 5533 is not an integer, we need to subtract a smaller number to make it a perfect square. We can try subtracting 1, 2, 3, and so on until we find a perfect square.

Trying to subtract smaller numbers:

1. Subtracting 1 from 5533:
5533 - 1 = 5532.

2. Finding the square root of 5532:
The square root of 5532 is approximately 74.372.

Again, the square root of 5532 is not an integer.

2. Subtracting 2 from 5533:
5533 - 2 = 5531.

3. Finding the square root of 5531:
The square root of 5531 is approximately 74.360.

Once again, the square root of 5531 is not an integer.

Continuing this process, we eventually find:

8. Subtracting 8 from 5533:
5533 - 8 = 5525.

9. Finding the square root of 5525:
The square root of 5525 is approximately 74.340.

Finally, we have found a perfect square. The number that must be subtracted from 5607 to obtain a perfect square is 5525.

Therefore, the correct answer is option C) 131.