Answer: A
Step-by-step explanation:
The -ane suffix implies that the compound has only single bonds for carbon-carbon bonds. The but- prefix implies that the compound consists of four carbons. Since 4 bonds are required for each carbon, there will be a total of 10 hydrogen atoms: 3 on each carbon at the end of the chain and 2 for each carbon in the middle of the chain. Thus, butane is A.