A compound X `(C_5H_8)` reacts with ammoniacal `AgNO_3` to give a white precipitate, and on oxidation with hot alkaline `KMnO_4` gives the acid, `(CH_3)_2CHCOOH`. Therefore , X is
A. `CH_2=CHCH=CHCH_3`
B. `CH_3(CH_2)_2C-=CH`
C. `(CH_3)_2CH-C-=CH`
D. `(CH_3)_2C=C=CH`