4. The teacher asked the students: "How many of you reviewed math yesterday?"
Zhang: "No one."
Li: "One person."
Wang: "Two people."
Zhao: "Three people."
Liu: "Four people."
The teacher knew that some of them reviewed yesterday afternoon, and some did not. Those who reviewed spoke the truth, and those who did not review told lies. Among these 5 people, the number of people who reviewed math yesterday is ( ) people.
(A) 0
(B) 1
(C) 2
(D) 3
Analysis: Only 1 of these 5 statements is true, so among these 5 people, 1 person studied math. Therefore, the answer is B.