The difference identity of two squares can be stated as:
a² - b² = (a + b)(a -b)
i.e. the product of sum of two numbers with the difference of two numbers. This can be easily proved.
For example, Let a = 4 and b = 3
so, a² - b² = 16 - 9 = 7
a + b = 4 + 3 = 7
a - b =4 - 3 = 1
(a + b )(a - b) = 7 x 1 = 7
Thus,
a² - b² = (a+b)(a-b)
So, option C gives the correct answer