If two options are marked in the NEET OMR sheet, it will be considered as an incorrect response. The OMR sheet is read by a machine which can only detect one response per question. Therefore, marking two options will lead to confusion and the machine will not be able to determine the correct answer. This will result in zero marks for that particular question.

Here is a detailed explanation of what happens if two options are marked in the NEET OMR sheet:

1. The OMR sheet is designed to detect only one response per question. If more than one response is detected, it will be considered as an incorrect response.

2. The machine reads the OMR sheet and identifies the marked responses. If two options are marked, the machine will not be able to determine the correct answer.

3. The OMR sheet is evaluated by a computer system. It is programmed to accept only one answer per question. If two options are marked, the computer will not consider it as a valid response.

4. In case of multiple responses, the machine will reject the answer and mark it as incorrect. This will lead to zero marks for that particular question.

5. It is important to mark the correct answer and avoid any confusion while filling up the OMR sheet. Any mistake in marking the answers can lead to a negative impact on the overall score.

In conclusion, it is essential to mark only one option in the NEET OMR sheet. Marking two options will lead to confusion and result in zero marks for that particular question. Therefore, it is advised to be cautious while filling up the OMR sheet and mark the correct answer without any errors.