4.   Which one of the following sentences contains two ideas joined by a connecting word? 

A. Frank went fishing on Saturday he caught many fish.
B. Mike ran after the bus.
C. Tina arrived at work earlier than usual.
D. Sally lives with her parents, although she could afford her own apartment.

D?

Yes. D is right.

Yes, the correct answer is D. Sally lives with her parents, although she could afford her own apartment.

To determine if a sentence contains two ideas joined by a connecting word, we need to look for coordinating conjunctions (such as "and," "but," "or," etc.) or subordinating conjunctions (such as "although," "because," "if," etc.) that connect two independent clauses or ideas.

In sentence D, the coordinating conjunction "although" connects the two independent clauses "Sally lives with her parents" and "she could afford her own apartment." Therefore, it contains two ideas joined by a connecting word.