A person can have 1 of 4 blood types: A, B, AB, or O. A Student determined that the probability that a randomly selected person has blood type O. What is wrong with his reasoning?

What was his level of probability? Since type O is the most prevalent blood type, it is the most probable.

The student's reasoning is incorrect because you have not provided the probability determined by the student. In order for me to assess the student's reasoning, I need to know what probability the student came up with. Could you please clarify the probability the student determined?