What is (are) the product(s) of the following reaction?

Question

Quizplus · Accepted Answer

The given reaction is a substitution reaction of a halogen with a primary alcohol in the presence of concentrated hydrochloric acid. The product(s) depend on the location of the halogen and the length of the carbon chain in the alcohol. 
I represents 1-chlorobutane, which is produced when the chlorination occurs at the primary carbon atom of the alcohol. 
II represents 4-chlorobutane, which is an isomer of I and is not formed in this reaction as there is no substitution at the secondary carbon atom. 
III represents butyl chloride, which is produced when the chlorination occurs at the terminal carbon of the alcohol. 
Since both I and III are formed in the reaction, the correct answer is D, only I and III.

What Is (Are) the Product(s) of the Following Reaction