OE

The queen's brothers became something to her spouse, the king. This gave “them the protection of King Magnus Eriksson in exchange for their homage (publicly expressed respect) and fealty (loyalty)”. By definition, a vassal is a person loyal or in service to a feudal lord. Proteges, vanguards, precursors, and partisans are all roles that people could serve on a king's behalf, but the sentence does not provide clues that indicate any of these meanings.
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In 1345, the brothers of Queen Blanche of Namur, Louis and Robert, were appointed (i) _______to her spouse, conveying upon them the protection of King Magnus Eriksson in exchange for their homage and fealty.

The sentence states that the brothers of Queen Blanche of Namur, were guaranteed protection by the King in exchange for their loyalty. This is an inferior position, and it is explicitly stated they had to also pay homage to the king.This leaves us with only vassals, and protege as a possible choice. But a protege is guided and supported by an older or experienced mentor whereas a vassal is a person under the protection of a feudal lord to whom he has vowed homage and fealty (loyalty).Thus Choice B, vassals is the correct choice.
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