The first thing we need to do to solve this question is to FORGET the definition of FOLLOW we know.
Here they have defined it in a bit new way (which might be some concept that we don’t know). Here FOLLOW can be calculated only in some sentential form and not in overall grammar as we do.
Now solving this logically.
When will you get the maximum number of terminals in the FOLLOW set as per their definition?
Obviously when we will first write terminals for the non-terminals on rightmost side i.e. RMD. Because non-terminals on the leftmost side will have more elements in their FOLLOW set.
Now using similar logic, when will we have minimum number of terminals in the FOLLOW set as per their definition?
Obviously, if we convert left most non-terminals to terminals first and let the right side non-terminals be as it is, then as per their definition we’ll have the minimum number of non-terminals in the FOLLOW sets.
I hope this is what they meant to ask. Please correct me if anything is wrong here.