Correct answer: This represents an S.H.M. of frequency ω/π.
The given equation x = a sin²ωt = a/2 (1 - cos 2ωt) represents a motion that is not simple harmonic motion (S.H.M.) because it involves a squared sine term, which leads to a frequency of 2ω, not ω/π. Thus, option D is correct as it correctly identifies the statement about frequency.