Choose the option nearest in meaning to the word underlined. His discovery of the vaccine became a quantum leap in search for a scientific cure for the illn...

Choose the option nearest in meaning to the word underlined.

His discovery of the vaccine became a quantum leap in search for a scientific cure for the illness?

Answer Details

The word "quantum leap" in this context means a significant and sudden improvement or breakthrough. Therefore, the option that is nearest in meaning to "quantum leap" is "great improvement."