Three circles of radii 3.5 cm, 4.5 cm and 5.5 cm touch each other externally. Then the perimeter of the triangle formed by joining the centres of the circles, in cm, is

A

27

B

$$π[(3.5)^{2} + (4.5)^{2} + (5.5)^{2} ]$$

C

27π

D

13.5