A Mass on a Spring Vibrates in Simple Harmonic Motion

Multiple Choice

A mass on a spring vibrates in simple harmonic motion at a frequency of 3.9 Hz and an amplitude of 7.8 cm.If a timer is started when its displacement is a maximum (hence x = 7.8 cm when t = 0) ,what is the displacement of the mass when t = 3.4 s?
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A) zero
B) -0.005 m
C) 0.079 m
D) -1.239 m
E) ​-0.01 m