The correct option is
B Frequency
The equation of motion for block,
ma=−kx or
a=−(k/m)xGeneral equation for SHM, a=−ω2x
So, angular frequency, ω2=k/m or ω=√k/m
Also, ω=2πf
Thus, frequency, f=12π√k/m
Hence, frequency is inversely proportional to the square root of block's mass.