B. Puerto Rico.
Don't think Cuba
Reserved powers are the powers that are not explicitly stated in a governing document but are implied powers because of other powers which are granted to the government. The creation of an education system or state identification systems are examples of reserved powers.
It would be "d. the Magna Carta" that was <span>signed by King John in the 1200s granting certain rights to the English people and limiting the king’s power, since Parliament practically forced him to do so. </span>