Organogenesis take place in the first trimester. Which of the following structure attains adult size before bih?

By 12 to 15 weeks, the ossicles are more clearly differentiated and approximate adult size. By the sixteenth week of gestation, the ossicles reach adult size. Sholy following this stage, ossification begins, first in the incus and last in the stapes. The external auditory meatus and tympanic membrane also reach adult size before term. Ref: Gray's anatomy, 39th edition, Page 470; Clinical Otology by Gordon B. Hughes, Myles L. Pensak, 2007, Chapter 1.