What is a mandate?

a. act of congress

c. presidential act of security

b. law enacted to ensure president power

d. expressed will of the people

A mandate is actually the expressed will of the people. The correct option among all the options given in the question is option "d". This term is used mainly in regards to democratic elections that are held. Mandate is the decision of the people that comes via the ballot box in case of free and fair elections for selecting representatives.