How Is the Japanese Prime Minister Elected

How is the Japanese prime minister elected?

A) By popular vote of the Japanese electorate
B) By a vote in both chambers of parliament, although the lower chamber's selection prevails if the two votes produce different candidates
C) Through "back room deals" among the various parties in the parliament producing the candidate that is essentially every party's second choice
D) By a vote in the lower house of the parliament
E) By a vote in the lower house of parliament that must be subsequently approved by the upper house