Discussion

Who is a horticulturist ?

Answer: A

A prefers tea. So, from (iv), the industrialist and D prefer coffee. But, from (iii), B and the journalist prefer coffee. So, B is the industrialist and D is the journalist.
Now, A, C and advocate remain. Clearly, E is the advocate.
The horticulturist is C's brother. It can be only A. C is a physicist.