Which formula can be used to find the tangential speed of an orbiting object

Tangential speed --> speed of something that is moving in a circular path) of an orbiting object is:
V₍t₎ = ωr
V₍t₎ = tangential speed or velocity
ω = angular velocity
r = radius of the circular path
if time taken t is only given then use this formula to calculate the tangential speed:
 V₍t₎ = 2πr/t,     t is time taken < -- 

I’d say a : water molecules

The answer is a if u read the definition it makes sense