A. Roman Catholic churches perform a mass, but Eastern Orthodox churches don't.
Explanation:
There are many differences between the Roman Catholic and Eastern Orthodox church, and one of them is that Catholic churches perform a mass, while Orthodox churches do not. They perform liturgies instead of masses.
The rest of the options are incorrect, because:
The pope heads Roman Catholic churches, while the patriarch heads Eastern Orthodox churches (not the other way around).
Both churches follow the New Testament.
Orthodox priests can be married if they got married before being ordained to the priesthood, but they are not allowed to enter marriage after ordination.
