An organic compound C₄H₈ₒ is found to be optically active. Which of the following could it be?
A. CH₃ - COCH₂ - CH₃ ₄ ₈ₒ
B. CH₃−CH₂ −CH₂ −CHO
C. (CH₃)₂ CHCOOH
D. CH₂ =CH−CH(OH)−CH₃