Answer the question on the basis of passage given below :
One of the notable features of the transition element is the great variety of oxidation states it may show in its compounds. The elements which give the greatest number of oxidation states occur in or near the middle of the series. Manganese, for example exhibits all the oxidation states from +2 to +7. The lesser number of oxidation states at the extreme ends is either due to losing or sharing of few electrons (Sc, Ti) or too many d electrons of higher valence. Early in the first series scandium (II) is virtually unknown and titanium (IV) which is more stable than Ti (III) or Ti (II). On the other end, the only oxidation state of zinc is \(+ 2\).
For balancing the given reaction, value of \(x\) will be.
\(4 FeCr_2 O_4+Na_2 CO_3+7 O_2 \longrightarrow x Na_2 CrO_4+2 Fe_2 O_3+8 CO_2\)

1. A 2
2. B 4
3. C 8
4. D 7