Ratna , who is in Mumbai , telephones her brother Ravi in Ahmedabad and speaks for 89 seconds . She is charged Rs 1.20 for every 16 seconds or part of 16 seconds . There is also a service charge of Rs 2 / - . Study the bill carefully . How much will it cost Ratna if she speaks to Ravi for 3 minutes ?
A) 14.40
B) 16.40
C) 18.40
D) 20.40
Please give explanation of your answer , please .