Suppose You Observe a Baby Sitting in Front of a Mirror

Suppose you observe a baby sitting in front of a mirror. You now place a dot of rouge on the baby's nose. You see the baby look at the mirror, but rather than focusing on the red nose, the baby appears to be looking at many aspects of her appearance. In fact, she begins to sing and do hand movements to her favorite song as if she is performing for her own enjoyment. Your best guess is that this baby is about how old?

A) about 6 months of age
B) about 12 months of age
C) about 18 months of age
D) 36 months of age