Select the option that will improve the underlined part of the given sentence. In case no improvement is needed, select 'No improvement'.
My friend walking quickly to the market and returned with a bag full of vegetables.

The sentence connects two actions using the coordinating conjunction "and". The second verb is given in the simple past tense ("returned").
To ensure proper structural parallelism across the coordinate clauses, the first action must also be written in the simple past tense.

"walking quickly" is a lone participle and is grammatically incomplete here.

walked quickly provides the required active simple past tense form.

Thus, 'walked quickly' is the correct improvement.