When the function \( f(x) = 2x \) is replaced by \( f(x - c) \) with \( c > 0 \), it undergoes a horizontal shift.
To analyze this, note that:
- Replacing \( x \) with \( x - c \) in the function results in shifting the graph to the right by \( c \) units.
So the correct statement is:
The exponential function undergoes a horizontal shift right \( c \) units.