A moral rule is regarded as justified by the deontologist if

1. it can be universalized.
2. it can be criticized.
3. it produces the best result.
4. it makes a person feel good

The correct answer is option 1: it can be universalized.

Deontologists believe in moral rules that are based on duty and are guided by principles that can be universally applied. According to deontological ethics, an action is morally acceptable if it is done in accordance with a moral rule that can be applied universally to all individuals in similar situations. This means that the moral rule must be applicable to everyone without exception and without contradicting itself.

To determine if a moral rule can be universalized, one can consider the following steps:

1. Formulate the moral rule: Clearly state the principle or rule that you are considering. For example, "It is always morally wrong to lie."

2. Universalize the rule: Imagine a world where everyone follows this rule in all circumstances. Ask yourself if this world would still function coherently and if the rule could be reasonably followed by everyone. In the case of the example, you would consider if a world where everyone always tells the truth is logically feasible and morally desirable.

3. Check for contradictions: Look for contradictions or inconsistencies that arise when the rule is universalized. Consider whether conflicts arise between the universalized rule and other moral or practical considerations. If the rule leads to contradictions or conflicts, it may not be suitable for universalization.

If the moral rule passes these tests and can be successfully universalized, it is regarded as justified according to deontological ethics.