Answer:
4
Step-by-step explanation:
A carbon atom has 4 electrons in its outermost shell (2s^2p^2). All are unpaired (none share their orbital with another electron). So all four are anxious to pair with another electron. Once it has found 4 more electrons contributed from other atom(s), it will have 4 pairs of shared electrons.
Hydrogen has one lone electron. An atom of H is downright gleeful in sharing it's electron with elements such as carbon, C. Since carbon has 4 unpaied electrons, it will combine with 4 H atoms. At that point, cabon is sharing 4 electron pairs.