Scaori Tribes made great use of the Kalahari pig: it was a s

Looking at answer choice A, there isn't anything obviously wrong right off the bat — we have two independent clauses (things that can stand on their own as complete sentences) separated by a colon (an acceptable use of a colon):

Scaori Tribes made great use of the Kalahari pig. It was a source of meat, and its hide was used for clothing, its hooves for fat, and its sinews and gut for bow strings.

We also have two independent clauses separated by a comma + and:

It was a source of meat. Its hide was used for clothing, its hooves for fat, and its sinews and gut for bow strings.

Finally, we have a parallel list:
-Its hide was used for clothing
-Its hooves (implied was used) for fat
-Its sinews and gut (implied were used) for bow strings

So we'll see if we can eliminate the other answer options.

B. We again have a comma + and, so everything before should be an independent clause, and everything after should be an independent clause:

It was a source of meat. Its hide used for clothing, with its hooves for fat, and its sinews and gut used for bow strings.

We notice that without "was" we don't have a verb after the comma + and, which means it isn't an independent clause, creating a comma splice.

We also see that our list is no longer parallel:
-Its hide used for clothing
-With its hooves for fat
-Its sinews and gut used for bow strings

Eliminate B.

C. "Which" after a colon is never, ever used — we *can* have a dependent clause after a colon, but "which" only ever follows a comma.

Our list is also no longer parallel:
-Its hide used for clothing
-Hooves for fat
-Its sinews and gut used for bow strings

Eliminate C.

D. Again, "which" after a colon is not acceptable. Similarly, the list is not parallel:
-Its hide was used for clothing
-Its hooves for fat
-Its sinews and gut were for bow strings

Eliminate D.

E. Like "which", "with" should follow a comma, not a colon. Similarly, breaking up "with its hide used for clothing" with "as well as being a source of meat" is an awkward and unclear construction. Finally, "being" is a common feature of unclear and wordy answer options. (Surprisingly, however, this list is parallel!) Eliminate E.

This leaves us with A as the correct answer.