The Dutch were the only Europeans allowed to trade with Japan as long as they .

a.

paid tribute to the emperor
b.

gave up all show of Christianity
c.

converted to Buddhism

d.

also traded with the Chinese

b. Gave up all show of Christianity.

Explanation:

The shogun Tokugawa Ieyasu had stamped out Christianity in Japan and allowed only the practice of the traditional Buddhism in the early 17th century. He mistrusted Catholic priests and traders, because they proselytized and wanted to win converts in Japan; here the shogun saw a threat to internal stability. He also forbade trade with the Europeans; the only exception were the Dutch. They were Protestants and weren´t interested in converting the Japanese. They were allowed to dock at Dejima, a small artificial island at the Nagasaki bay. They traded with Japan, paid tribute to the shogun,  and also served as a source of news about the outside world for Japanese rulers.

b

make me

i would say your answer is a)

sorry if im wrong