What was the role of a bishop in the catholic church?

a. a person who supervises a number of local churches or a diocese.

b. a high ecclesiastic appointed by the pope to the college of cardinals and
ranking above every other ecclesiastic but the pope.

c. a person whose office it is to perform religious rites, and especially to make
sacrificial offerings.

d. the bishop of rome as head of the roman catholic church.

e. a bishop of the highest rank who presides over an archbishopric or
archdiocese.

f. a member of the clergy employed to assist a rector or vicar.