We should do away with the present examination system. A. prohibit B. demolish C. extend D. abolish

The correct answer is D. abolish.

To abolish something means to completely get rid of it. In this case, the speaker is suggesting that we should completely get rid of the present examination system.

The other options are not as accurate.

• Prohibit means to make something illegal. The speaker is not suggesting that we make the examination system illegal.
• Demolish means to destroy something. The speaker is not suggesting that we destroy the examination system.
• Extend means to make something longer or larger. The speaker is not suggesting that we make the examination system longer or larger.

In conclusion, the correct answer is D. abolish.