Assertion: Carbon atom is tetravalent though it has two unpaired electrons.
C has atomic number 6. It has 4 electrons in its valence shell. Carbon can either donate all 4 electrons or it can accept 4 electrons to become stable.
Hence it is termed as tetravalent.
Ground state electronic configuration of carbon is 1s2, 2s2, 2p2.
There is a probability of the formation of four bonds is maximum. So, in the
formation of one molecule of CH4, there will be a combination of 1 C atom
with 4 H atoms.
C has uniquely had one of the p-orbitals bonding with the other two p-orbital for making the π−bonds. Thus p-orbital pointing toward the other atom cannot make π−bond.
The first member of a group differs from the heavier members in its ability to form pπ - pπ multiple bonds to itself. (carbon)
Both are true, but the reason is not correctly related to the assertion.
Option B is correct.