What Is the Null Hypothesis When Performing an F-Test to Test

Multiple Choice

What is the null hypothesis when performing an F-test to test the strength of an instrument?

A) the instrument is weak,with no $\theta$ different from 0.
B) it is a strong instrument with all $\theta$ significantly different from 0.
C) the instrument is sufficiently strong with at least 1 $\theta$ significantly different from 0.
D) the instrument is weak with all $\theta$ different from 0.