Silicon pvt ltd is a reputed company, which is having around 1000’s employees working in their company. one day, one of the employees approached the authorized person of the organization claiming that he/she forgot their id badge and requested the person to allow through a secure door. whereas the authorized person believed that the person forgot the id badge and the person to go through the entrance by swiping with his/her id badge. later on that authorized person realized that the person is a non-employee of the organization and he/she is an intruder who intentionally entered into the company from the above scenario, which of the following comes under the human-based social engineering

a. tailgating
b. piggybacking
c. reverse social engineering
d. none of the above