To develop this problem it is necessary to apply the concepts related to the Frequency according to the Period. Frequency is the number of repetitions per unit of time of any periodic event. The period is the length of time of each repetitive event, so the period is the reciprocal of the frequency.
The frequency of the metronome in seconds would then be


Since the frequency is inversely proportional to the period then



The correct answer is B. 375ms