`CH_(3)-underset(CH_(3))underset(|)(C)H-CH_(2)-underset(CH_(3))underset(|)(C)H-CH_(2)-CH_(3)underset(800^(@)C)overset(Cr_(2)O_(3)//Al_(2)O_(3))to` Find the X.
A. `CH_(3)-underset(CH_(3))underset(|)overset(CH_(3))overset(|)(C)-C-underset(CH_(3))underset(|)overset(CH_(3))overset(|)(C)H_(2)-CH_(3)`
B. `CH_(3)-underset(CH_(3))underset(|)overset(CH_(3))overset(|)(C)-C-underset(CH_(3))underset(|)overset(CH_(3))overset(|)(C)H_(2)-CH_(3)`
C.
D.