In situational irony -

a. what is said is the opposite of what is meant

b. someone behaves deceptively toward people who trust him or her

c. what is expected is the opposite of what happens

d. the actors know something that the characters they play don't know

In situational irony:

c. what is expected is the opposite of what happens

This type of irony is also known as the irony of events where sharp contrasts are illustrated on the difference between predictions and the reality which is one concrete example. This can create various reactions from audiences given that they are provided with all the chances of thinking out of the box.