For this particular question we would be looking into the opposite of the given word "Eclipse".
Eclipse means an obscuring of the light from one celestial body by the passage of another between it and the observer or between it and its source of illumination. The opposite would be to give out a bright light i.e. shine.
If we look into the other options,
Enlarge is to make or become larger or more extensive
Google is to search for information about (someone or something) on the Internet using the search engine Google
Gleam shine brightly, especially with reflected light.
Option A is correct