The correct options are
B He was once chosen to represent his monastery in Rome.
D He was a theologist.
Martin Luther was a German monk and a theologist who studied the Christian religion. As a devout Christian, Luther pictured Rome as a holy place, an epitome of purity. He visited Rome which proved to be one of the most disappointing episodes of his life. He found himself distressed by the corruption of the priests, their tales of immorality, and their luxurious houses.