Question

brusquely means :
not seriously
without knowledge
in a blunt direct manner
in a friendly manner

Explanation:

The word "brusquely" is an adverb meaning in a blunt, abrupt, or direct manner. Analyzing each option, "not seriously" is off - topic, "without knowledge" is unrelated, and "in a friendly manner" is the opposite. The correct meaning is "in a blunt direct manner".

Answer:

in a blunt direct manner