Correct Answer: Darkened

Solution : The correct choice will be the first option.

Flared: It refers to expanded outward; widened or spread out, often referring to something becoming broader at one end.

Darkened: It means made or became dark; the opposite of lightening or brightening.

In this context, darkened serves as the most fitting antonym as it represents the opposite action of spreading or expanding, suggesting a reduction in brightness or light.

The meanings of the other options are:

Radiated: Although it involves spreading out, it doesn't capture the sense of expanding outward as "flared" does.

Flamed: While it involves fire, it doesn't convey the sense of widening or spreading outward.

Glared: It involves a fixed and intense gaze but doesn't relate to the concept of expanding or spreading.

Therefore, the correct answer will be darkened.