Hi,
The request actually is to choose functions whose derivative is a constant.
For A, derivative is [tex]\dfrac{1}{2\sqrt x}[/tex], which is not constant.
For B, derivative is 2ˣ·ln2, which is not constant.
For C, derivative is 0, which is a constant.
For D, derivative is 1, which is a constant.
So, you can choose C and D.
Have you understood ?
Green eyes.
