In the following question, a sentence / a part of sentence is underlined. Below are given alternatives to the underlined part which may improve the sentence. Choose the correct alternative. In case no improvement is required, choose "No Improvement" option.
A sentence has been given in Active/Passive Voice. Out of the four given alternatives, select the one which best expresses the same sentence in Passive/Active Voice.
The HIV virus continuously invades and destroys T-cells (lymphocytes). Eventually the body can't replace the T-cells fast enough, and the immune system deteriorates. When the immune system has deteriorated to the point that it is unable to fight off diseases, a person is diagnosed with AIDS.