The correct option is A 240 miles
The Salt March, which took place from March to April 1930 in India, was an act of civil disobedience led by Mohandas Gandhi to protest British rule in India. During the march, thousands of Indians followed Gandhi from his religious retreat near Ahmedabad to the Arabian Sea coast, a distance of some 240 miles. Hence, Option A is correct. Among the rest, none of these estimates correspond to the one recorded, hence, incorrect.