Two clarinets are playing the note A at $440$ Hz $.$ Suppose $($unrealistically$)$ that the sound waves from the two clarinets are coherent. Which of the following path length differences do not result in totally destructive interference? Take the speed of sound to be $343\frac{m}{s}.$

Select one:

a$.,1\mathrm{.}17m$

$$ b$.3\mathrm{.}51$ m

c$.4\mathrm{.}68$ m

$$ d$.6\mathrm{.}63$ m