Person A, of course. This person is the original maker of the image therefore that person has the rights to that image, person B does not automatically become the owner just by using it on his website. So the answer is person A.
Your answer would be 5098 liters.
Reason being, because there are 1,000,000 liters in one megalitre, so you just multiply 0.005098 by 1,000,000 to get your answer of 5098 liters.
She should figure determine what her main goal is and compare telecommunication devices. Then she should weigh the advantages and disadvantages of each device, and choose which one suits the job best.