In the Middle Ages,Spain Had Many Castles Because

Multiple Choice

In the Middle Ages,Spain had many castles because:

A) King Alfonso II built them to protect his united kingdom from French incursions.
B) they were built by the church to protect their properties.
C) they were built by different factions competing for power in the Middle Ages.
D) they were built to defend the Spanish border from Portuguese raiders.
E) they were built to defend Spain from Viking raids.