Explanation:

The given sentence is in the imperative form, which is used to give commands or advice. In this case, it is giving advice or caution to someone about the possibility of being cheated. The correct sentence should convey this caution effectively.

Analysis of options:

a) that you will not be cheated
This option changes the verb "are" to "will be," which changes the meaning of the sentence. It suggests that the cheating will happen in the future, rather than cautioning against it in the present. Therefore, this option is incorrect.

b) you will not be cheated
This option removes the word "that" from the sentence, which changes the structure and meaning. The word "that" is necessary to introduce the subordinate clause and convey the caution effectively. Therefore, this option is incorrect.

c) that you are not cheated
This option maintains the structure and meaning of the original sentence. It effectively conveys the caution to the person, ensuring they are aware of the possibility of being cheated in the present. Therefore, this option is correct.

d) No improvement
This option suggests that the original sentence is already correct and does not require any changes. However, as explained above, option c) provides the correct structure and meaning, making it a better choice than the original sentence. Therefore, this option is incorrect.

Conclusion:

Option c) "that you are not cheated" is the correct answer as it maintains the original structure and effectively conveys the caution to the person.