Answer:
C. Irony
Step-by-step explanation:
According to the given sentence, the author talks about people thinking they are liberated because they can take their phone anywhere.
This statement brings a sense of irony because the speaker clearly believes that people are not liberated because they are in fact imprisoned by their attachment/addiction to their mobile phone.
Irony is defined as a situation where events are contrary to what one expects and can be amusing.