The correct answer is C. Christians and Jews worshipped one God.
Moorish rulers in Spain were initially somewhat tolerant of Christians and Jews partly because of the shared monotheistic belief in one God. This created a basis for relative tolerance compared to other regions or periods where religious differences led to more persecution. They were often seen as "People of the Book," which afforded them certain protections under Islamic rule, although this tolerance could vary depending on the time and the specific rulers.