You're correct, the answer is C.
Given any function of the form

, then the derivative of y with respect to x (

) is written as:

In which

is any constant, this is called the power rule for differentiation.
For this example we have

, first lets get rid of the quotient and write the expression in the form

:

Now we can directly apply the rule stated at the beginning (in which

):

Note that whenever we differentiate a function, we simply "ignore" the constants (we take them out of the derivative).
Answer:
Her z-score is 2.03.
Step-by-step explanation:
In a set with mean
and standard deviation
, the zscore of a measure X is given by:

Michelle’s height is 1.758 meters. What is her z-score?
Michelle's is a woman.
The average height of women is
and the standard deviation is 
This is Z when X = 1.758. So



Her z-score is 2.03.