Final answer:
The minimum number of students in a class such that at least four of them must be born in the same month is 12.
Step-by-step explanation:
To find the minimum number of students in a class such that at least four of them must be born in the same month, we need to consider the worst-case scenario. The worst-case scenario occurs when three students are born in each of the first eleven months, and the remaining student is born in the twelfth month. In this scenario, we would need at least 12 students to ensure that at least four of them are born in the same month.