Answer:
<em><u>A) Alive, the elephant was worth at least a hundred pounds; dead, he would only be worth the value of his tusks, five pounds, possibly. </u></em>
Explanation:
Semicolons are used to indicate a pause longer than that of a comma, but shorter thant that of a period.
When you have two independent clauses whose ideas are closely related, the semicolin is commonly use to link both clauses
Let's see every sentence.
<em>B) Alive, the elephant was worth at least a hundred pounds. Dead; he would only be worth the value of his tusks, five pounds, possibly.</em>
The pause after <em>"Dead"</em> should be equal as the pause after <em>Alive</em>. The comma after Alive is correctly used because that is a very short pause. Thus, after <em>Dead</em> there should be a comma, not a semicolon.
<em>C) Alive, the elephant was worth at least a hundred pounds. Dead, he would only be worth the value of his tusks; five pounds, possibly.</em>
What comes after "<em>tusks"</em> is a further detail (explanation) about what the value of the <em>tusks</em> could be; thus, there should be a comma not a semicolon.
D) Alive, the elephant was worth at least a hundred pounds and; dead, he <em>would only be worth the value of his tusks, five pounds, possibly. </em>
Using a semicolon after <em>"and"</em> is a msitake because you should not add a pause after the conjunction.
The first sentence, <em>A) Alive, the elephant was worth at least a hundred pounds; dead, he would only be worth the value of his tusks, five pounds, possibly, </em>correctly implements the semicolon after the first clause, to link with the second clause, with an intermediate pause.