Strong carbon-carbon bond is present in

[Step 1]:Strength of the carbon-carbon bond increases with increase in number of bonds  between carbon and carbon.[Step 2]:In option (1) CH3−CH3  number of bonds between carbon and carbon is one.[Step 3]:In option (2)CH2=CH2  number of bonds between carbon and carbon are two.[Step 4]:In option (3) CH4 there is no carbon-carbon bonds.[Step 5]:In option (4) HC≡CH  number of bonds between carbon and carbon are three.