Final answer:
The pulse duration is related to and expressed in the same units as the period of a wave, which is time, making A. Period the correct answer.
Step-by-step explanation:
The pulse duration of a wave refers to the length of time for which the pulse is present, and it is typically measured in units of time, such as seconds. This measurement is related to the period of a wave, which is also a time measurement - the time it takes for one complete cycle of the wave, such as from crest to crest or trough to trough. The correct answer to the question is thus A. Period.
While wavelength represents the spatial measurement between two identical points on successive waves, such as between two crests, and is measured in units of length (meters, centimeters, etc.), pulse duration is not measured in these units. Therefore, the similarity between pulse duration and period is that both are expressed in units of time (seconds), making period and pulse duration directly relatable.