Question

before henry ford revolutionized the automobile industry, most cars were made
on an assembly line.
one at a time, by hand.
by unskilled workers.
using a disassembly line.

Explanation:

Before Henry Ford introduced the assembly - line method, car production was a slow, manual process. Cars were crafted one at a time by skilled workers, not on assembly or disassembly lines, and not by unskilled workers.

Answer:

one at a time, by hand.