Defence Research and Development Organisation (DRDO) is an agency of the Republic of India, charged with the military's research and development

As you are asking for Answer Key of DRDO burt of which exam you did not mention , so due to it I am telling only process by which you can get Answer Key of DRDO any exam, if avail on its official website

Step 1: Visit to the DRDO website.

Step 2: Look for the Answer Key Link or Category.

Step 3: Select your Paper Code.

Step 4: Download the PDF File of Answer Key.

Step: 5 Match Your Answers and Calculate Your Score.

Address

Defence Research and Development Organisation
P and T Colony, P&T Colony, Civil Lines
New Delhi, Delhi (state) 110054