B. In the secluded pond, frogs and mallard ducks swim.
Along With and As Well As Do Not Form Plural Subjects
Beware of words that join but do not qualify as true conjunctions and thus do not form plural subjects. These words include as well as, along with, together with, not to mention, and others. Again, another example from New Fowler:
A very profitable company such as British Telecom, along with many other companies in the UK, is not prepared to pay a reasonable amount. New Fowler, p. 35.
Neither-Nor, Subject-Verb Agreement
The problem of subject-verb agreement also crops up when you use correlative conjunctions. When you use neither . . . nor to join two subjects of a clause, you will confront the problem of number. Must the verb appear in the singular or the plural? When neither . . . nor joins two singular subjects, the verb must be singular as well. Like this:
Neither the player nor the coach wants to lose the game.
The main verb would be "indicated", being that "research" (which is the main subject) is what's doing the action, which is indicating.
The whole sentence is basically about the research indicating... etc.
