3.a. The name of this book is CatcherThe Catcher in the Rye.
3.b. CatcherThe Catcher in the Rye is the name of this book.
- It (The name of this book)'s CatcherThe Catcher in the Rye.
I’ve come up with some sort of rule to identify whether the wh-word asks for the subject or for the subject complement, which consists of checking the position the reply to "what”, “who” or “which” will occupy in the answer to the question. Perhaps, as Cascabel said, this belongs on ELL, but since the question has been posed on ELU and has not been migrated (at least, not for the time being), I’d appreciate your comments:
Q2: What is the most popular sport in America?
A2: Football is the most popular sport in America.
“what” may be considered to be in subject position, because it can be replaced with “football” in that front position in the answer. This accounts for the correctness of the short answer “Football is,” and also for the order of the words if the question is embedded:
Embedded Q2: He wants to know what is the most popular sport in America.
(what: subject / is: verb / the most popular sport in America: subject complement)
Alternatively, we can consider that "what" (and "football") is in subject complement position:
Q2': What is the most popular sport in America?
A2': The most popular sport in America is football.
In this case, the embedded question will be different:
Embedded Q2': He wants to know what the most popular sport in America is.
(what: subject complement / the most popular sport in America: subject complement / is: verb)
Let’s see what happens with the other question:
Q3: What is the name of this book?
A3: (It’s) The Catcher in the Rye.
In this case, “what” is in subject complement position, and that accounts for the awkwardness of the answer “The Catcher in the Rye is.” To further prove this point, we can check what happens when the question is embedded:
Embedded Q3: He wants to know what the name of this book is. (I don't think He wants to know what is the name of this book is a good reported question.) (Therefore: what: subject complement / the name of this book: subject / is: verb)
(I admit that other indirect questions would sound more natural, like “He wants to know the name/title of this book” or “He wants to know what this book is called” where, again, “this book” is subject and “what” asks for the subject complement.)