Question

1. which modification of the output signal changes the shape?

a frequency
b amplitude
c dc offset
d symmetry

Explanation:

Changing the frequency of a signal alters the number of cycles in a given time - period, which changes its shape. Changing amplitude just scales the height of the signal, DC offset shifts it up or down, and symmetry is a property that may or may not be affected by other modifications but is not a direct modifier of shape like frequency.

Answer:

A. Frequency