The correct increasing order of the reactivity of halides for `S_(N^(1))` reaction is:
A. `CH_(3)CH_(2)X lt (CH_(3))_(2)CHX lt CH_(2)=CHCH_(2)X lt PhCH_(2)X`
B. `(CH_(3))_(2)CHX lt CH_(3)CH_(2)X lt CH_(2)=CHCH_(2)X lt PhCH_(2)X`
C. `PhCH_(2)X lt (CH_(3))_(2)CHX lt CH_(3)CH_(2)X lt CH_(2)=CHCH_(2)X`
D. `CH_(2)=CHCH_(2)X lt PhCH_(2)X lt (CH_(3))_(2)CHX lt CH_(3)CH_(2)X`