An Attacker Watches People as They Enter a Building Requiring

An attacker watches people as they enter a building requiring a key card.He waits until he see someone who appears to be in a rush and has their hands full.He then intercepts the person,makes quick small talk,offers to help them hold what's in their hands while he swipes in,and follows behind.This is an example of

A) Spear phishing
B) Pharming
C) Piggybacking
D) Man trapping