Val taps two different tuning forks at the same time. The resulting sound has a frequency of $852$ Hz $,$ but its volume oscillates up and down. If one of the tuning forks produces a $855$ Hz note, what is the beat frequency of the interfering sound waves?

Select one:

a$.1\mathrm{.}5$ Hz

b$.3$ Hz

c$.4\mathrm{.}5$ Hz

d$.6$ Hz