Darlene Is Excited by the Fact She Has Learned to Turn

Darlene is excited by the fact she has learned to turn the dial on the dishwasher.Every chance she gets,she turns the knob to hear the noise it makes.Based on this description,how old is Darlene?

A) 4 months old
B) 6 months old
C) 8 months old
D) 10 months old