Source: KAPLAN 800

Constructed with the finest Italian marble, the floor of the church is its greatest attraction and is more attractive to tourists than are its ornate stained-glass windows.

A: attraction and is more attractive to tourists than are its ornate stained-glass windows
B: attraction, itself more attractive to tourists than are its ornate stained-glass windows
C: attraction, itself more attractive to tourists as are its ornate stained-glass windows =>INCORRECT
D: attraction, being more attractive to tourists than its ornate stained-glass windows are =>INCORRECT
E: attraction as if more is attractive to tourists than are its ornate stained-glass windows =>INCORRECT

OA: B

I believe that "itself more attractive to tourists than are its ornate stained-glass windows" is an absolute phrase. Is it right?

Why verb (ARE) is plural?

What would be the criteria to select A or B?

" ... than are its ornate stained-glass windows" => it compared with "to tourists"
" ... than its ornate stained-glass windows are" => it compared with "the floor"