A seems to be only possible answer choice.

Jorge says that Ruth can't write well about that period because she's not old enough.

Thus, Jorge views "being old enough" as a qualification for even being considered to write well. In other words, one cannot write well if one is unqualified to do so. Note that this does not mean that just because a person is old enough, their writing will be good.

But being old enough is the first prerequisite, in Jorge's view.

And Ruth disagrees. She does not believe that her "youth ALONE" will prevent her from writing well.

only answer choice which describes this is A

Jorge does raises a doubt whether Ruth will be able to write or not. And B i feel is not correct because Ruth question Jorge on whether he will be able to write not on whether people in their teens and twenties will be able to write it.

IMO B

What is the issue between Jorge and Ruth ?
J: Ruth won’t be able to write well about the rock music of the 1960s since she was an infant then . Rock music of the 1960s was created by and for people teens and early twenties
R: Living writers write well about ancient Roman culture, even when they were not born, Youth wont prevent her to write about songs

(A) whether only those people who were in their teens or early twenties during the 1960s can be qualified to write about the rock music of that period
Too extreme for a difference - > Out

(B) whether people who were in their teens or early twenties during the 1960s can write well about the rock music of that period
Now if i say
Yes people who were in their teens or early twenties during the 1960s can write well about the rock music of that period -> this strengthens the claim made by Ruth
No people who were in their teens or early twenties during the 1960s cannot write well about the rock music of that period -> this questions the claim made by Ruth

(C) whether only people who are past their early twenties can write well about ancient cultures
ancient cultures- we need to talk about the music -> Out

(D) whether people who are not now in their teens or early twenties can write well about the rock music of the 1960s
Not now in their teens, people of this demographic are irrelevant for the argument -> Out

(E) whether Ruth’s ideas about the rock music of the 1960s are likely to appeal to people who were in their teens or early twenties during that period
Argument didnt mention about the appeal -> Out
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easy A.I see B is a contender.

Ruth does not touch upon what teens in the 1960s can or can't do.His point is "Somebody past a period can write about that period".