Which sentence best relates an example in an objective manner?

Industry needed to reach a broad market for its desirable products.

It was amazing that farmers in the Northwest Territory could produce such large crops.

Two large canal systems linked Eastern manufacturers with the Northwest Territory.

The railways ran through the beautiful scenery of the Great Lakes and rolling farmlands.

The answer is the option C. Two large canal systems linked Eastern manufacturers with the Northwest Territory.

That sentence contains a fact that is based on the object or objects not the subject that tells the sentence. The same facts can be proven by any subject. This is the information given is not based on the subject opinion buth onthe the very objects. That is whan an objective sentence means.

On the other hand the other sentences contains information that dependes on the subject that tells the sentence. needed (based on what or who?), amazing, beautiful. Those are opinions which can vary depending onthe subject that tells the opinion; that is what subjective is.