Using college students as the market segment describe the most relevant reference group(s) and indicate the probable

Question:

Using college students as the market segment describe the most relevant reference group(s) and indicate the probable degree of influence on decisions for each of the following:
a) Brand of toothpaste:
b) Purchase of hybrid car:
c) Purchase of breakfast cereal:
d) Becoming a vegetarian:
e) Choice of computer tablet such as the iPad: