Select the most appropriate option to substitute the underlined segment in the given sentence. If there is no need to substitute it, Select No improvement.As a result of various inventions during Victoria's reign, travel and communication became better and improved sanitation techniques turn filthy streets in clean roads.

• A. turn filthy streets into clean roads.
• B. turned filthy streets into clean roads.
• C. turning filthy streets in clean roads.
• D. No improvement