A man who always . . . . . . . . at the faults of his children is their worst enemy. A. appears B. connives C. happy D. abstain

The correct answer is B. connives.

To connive means to secretly agree to or help someone do something wrong or harmful. In this case, the man who always connives at the faults of his children is helping them to continue making mistakes and not learn from them. This is harmful to the children, as it will prevent them from growing and developing into healthy, responsible adults.

The other options are incorrect for the following reasons:

• A. appears means to seem or look like something. This does not make sense in the context of the sentence, as the man is not simply appearing to connive at the faults of his children, he is actually doing it.
• C. happy means feeling or showing pleasure or contentment. This does not make sense in the context of the sentence, as the man who always connives at the faults of his children is not doing something that is likely to make him happy.
• D. abstain means to refrain from doing something. This does not make sense in the context of the sentence, as the man who always connives at the faults of his children is not refraining from doing something, he is actually doing it.