Answer:
The first one height vs shoe size.
Explanation:
Let's evaluate each choice
1) Generally, it is possible that the taller a person is, that his/her shoe size would generally get bigger also. Hence we can say that it is possible that there is a function correlation between height and shoe size.
2) hair length can be cut down short or left long regardless of the height of a person, so we cannot say for sure that hair length correlates with height. Hence this is probably not a function)
3) hair color has no bearing on a persons age. hence this is probably not a function.
4) student ID number doesn't depend on the name of the student. Hence this is probably not a function.