A primary alcohol is one in which the carbon atom attached to the –OH group is connected to only one other carbon atom. In option (A), CH\(_3\)CH\(_2\)CH\(_2\)OH (1-propanol), the –OH group is attached to the terminal carbon which is bonded to only one carbon atom, making it a primary alcohol.
Option (B) is a secondary alcohol (2-propanol), and option (C) is a tertiary alcohol (tert-butanol).