The correct options are
A Agastyar
D Madurai
Sage Agastyar founded the seat of the First Sangam at Old Madurai. Sage Agastyar also founded the Second Sangam, but at Kapatapuram after the city of old Madurai was submerged by the sea. Kapatapuram was swept away by the sea, and the Third Sangam was established in present-day Madurai.