question_answer

The sides of an equilateral triangle are \[\left( \text{2a}-\text{b} \right)\] cm, \[\left( \text{a}+\text{3b} \right)\]cm and \[\left( \text{2a}-\text{2b}+\text{1} \right)\] cm, then the perimeter of the triangle is

A)  3 cm                     

B)  12cm

C)  15cm                   

D)  21cm