The most important reason to know basic first aid is:
a.
it is the best way to treat minor cuts and bruises
b.
it reduces the number of accidents in a workplace
c.
it is company policy in many workplaces
d.
it allows emergencies to be treated swiftly

The most important reason to know basic first aid is because it allows emergencies to be treated swiftly. The correct option among all the options that are given in the question is the last option or option "d". Under critical medical situations, the knowledge of basic first aid can be a life saver for a person.