Let's simplify each expression shown in the exercise:
Option a
Given:

You can apply the Product of powers property. This states the following:

Where "b" is the base and "n" and "m" are exponents.
Then, you get:

By definition:

Therefore:

The expression given in Option a is equal to 1.
Option b
Knowing that any number or expression with exponent zero is equal to 1, you get that:

The expression given in Option b is equal to 1.
Option c
Given:

You can notice that the numerator and the denominator are equal, then:

The expression given in Option c is equal to 1.
Option d
Given:

You can simplify it using the Quotient of powers property, which states that:

Then, you get:

The expression given in Option d is not equal to 1.
The answer is: Option d.