The correct option is A Varkari Keertans involve a group performance whereas Haridasi Keertan is a solo performance.
Keertans are of two types, Naradiya or Haridasi Keertans and Varkari Keertans. Haridasi Keertans are mainly solo performances. They consist of two parts: The Poorvarang and The Uttrarang. Varkari Keertans usually involve a group performance with the help of Taal musicians.