Select the INCORRECTLY spelt word.

The correct option is Conscientous.

Explanation:

Let us analyze the spelling of the given words:

1. Apparent: Correctly spelt. It means clearly visible or understood; obvious.

2. Acknowledgment: Correctly spelt. It refers to acceptance of the truth or existence of something.

3. Fulfil: Correctly spelt. It means to achieve or realize something desired, promised, or predicted.

4. Conscientous: Incorrectly spelt. The correct spelling is Conscientious (it is missing the letter 'i' after 't'). It means wishing to do one's work or duty well and thoroughly.

Therefore, the incorrectly spelt word is Conscientous.