Parts of a sentence are given below in jumbled order. Arrange the parts in the correct order to form a meaningful sentence.

A great transition / marked / the $$20^{th}$$ century / for mankind

A

A great transition marked the $$20^{th}$$ century for mankind.

B

The $$20^{th}$$ century marked a great transition for mankind.

C

A great transition for mankind marked the $$20^{th}$$ century.

D

For mankind, a great transition marked the $$20^{th}$$ century.