For this question, choose the option opposite in meaning to the word or phrase in italics. He made a facile generalisation.

Facile means appearing neat and comprehensive but lacking depth or careful thought; superficial, simplistic, or too easily achieved. A facile generalisation is one that oversimplifies a matter without engaging with its real complexity.

The word opposite in meaning is complex, which means consisting of many interconnected parts; not simple or straightforward. A complex generalisation would be one that engages with the full difficulty and nuance of a subject - the direct opposite of a facile, oversimplified one.

The other options do not serve as antonyms:

• broad means wide in scope or extent. A generalisation can be both broad and facile, so this is not an opposite.
• quiet means making little noise or said in a soft voice. This describes volume or manner of speaking, not the quality of thought behind a statement.
• careful means done with attention and thought. While closer to an antonym than the other two, it describes the process rather than the nature of the generalisation itself; complex more directly opposes the superficiality that facile implies.