3. Select all the sectors which have an area of 3pi square units.
a)a sector with a radius of 6 units and a central angle of 30 degrees
b)a sector with a radius of 6 units and a central angle of 45 degrees
c)a sector with a radius of 3 units and a central angle of 60 degrees
d)a sector with a radius of 3 units and a central angle of 120 degrees
e)a sector with a radius of 3 units and a central angle of 180 degrees