Which type of music is a secular musical form of the medieval era?

gregorian chant
estampie
plainchant
a cappella

Plainchant is a kind of music that is  secular medieval musical form

Explanation:

Plainchant is a kind of music that is  secular medieval musical form

Medieval music was written and developed for several different musical forms for a certain voice or instrumental songs. Medieval time  music developed for the religious and spiritual use of church. The liturgical genre primarily Gregorian chant, was monophonic in early mediaeval period.

giovanni battista pergolesi, italian baroque composer who wrote one of the most famous settings of the stabat mater. don lorenzo perosi, catholic priest and director of the sistine choir under five popes.