The correct option is A 2-chloro-2-methylpropane
Tertiary butyl chloride is an organochloride with formula (CH3)3CCl. The longest continuous chain of carbons is 3. It is propane. The remaining groups are chloro and methyl. Both are at position 2. Chlorine comes before methyl in the alphabet, so the IUPAC name of tertiary butyl chloride is 2-chloro-2-methylpropane.