B) C₇H₁₄
C₄H₁₀, C₅H₁₂, and C₂H₆ are alkanes (general formula CₙH₂ₙ₊₂), whereas C₇H₁₄ follows CₙH₂ₙ, making it an alkene or cycloalkane — different from the others.
The key is identifying the homologous series. Alkanes follow CₙH₂ₙ₊₂: C₂H₆ ✓, C₄H₁₀ ✓, C₅H₁₂ ✓. C₇H₁₄ follows CₙH₂ₙ (alkene/cycloalkane series), so it is the odd one out.