Answer:
D/B ahs units of Length over Time
Step-by-step explanation:
Notice that B is multiplying "x" (displacement) as argument of the sine function, therefore it has to have units of the reciprocal of Length.
Also the constant D is multiplying "t" as argument of the sine function, and as such, it must have units of the reciprocal of time.
Therefore, the quantity D/B must have units of Length over Time.