<u>D. </u><u><em>c=ab-d/a is the correct answer.</em></u>First you had to add by -ab from both sides of equation, and it gave us, , or . Then divide by -a from both sides of equation, and it gave us, , and it gave us the answer is<u><em> </em></u><u><em>c=ab-d/a is the right answer.</em></u>Hope this helps! And thank you for posting your question at here on brainly, and have a great day. -Charlie