The correct option is C Deepthi
Let Geeta's age be G,Seetha's be S,Deepthi's be D.and Shankar's be Sh.
Given: G=2+S,S=3+D and Sh=D+1
writing all in terms of D we get, G=5+D , S=3+D & Sh=D+1=> G,S & Sh are older than D or D is the youngest.
Hence, option 'D' is correct.