Question

a green underline in ms word indicates a ........................................ option grammatical , word art

Answer 1

it is used to indicate any grammatical errors

Answer 2

If there is a spelling mistake, the word gets underlined with a red color wavy / squiggly / zig-zag line indicating the error. For grammatical errors a wavy green line appears under the word or phrases. So, all in all, these red-green wavy underlines indicate spelling and grammar mistakes.