Which of the parts are correctly grouped?

The diagram above is an illustration of some parts of a mammalian ear. Study it and answer this question.

A. (Inner ear I, IV) (Middle ear III) (Outer ear II)
B. (Inner ear III) (Middle ear II, IV) (Outer ear I)
C. (Inner ear III) (Middle ear II) (Outer ear III,IV)
D. (Inner ear II) (Middle ear I, III) (Outer ear IV)

Correct Answer:

Option D = (Inner ear II) (Middle ear I, III) (Outer ear IV)