Exp) Option b is the correct answer.

The Fanam coins were the regular unit of currency in medieval Travancore and appear to have been extensively used for trading in the region of South India. The words Fanam and Panam literally mean money and are still used as a synonym for wealth in Kerala in the native language of Malayalam.

Sources: 

http://www.columbia.edu/itc/mealac/pritchett/00glossarydata/terms/fanam/fanam.html