Apologize

After explaining what happened, the next step is to apologize:

Good apologies

The apology above is excellent. In general, use this structure for apologies:

Such apologies show that you own your mistakes and don't try to make excuses.

Bad apologies

Here are some examples of bad apologies that do not follow the above structure.

By using the passive voice, you fail to take responsibility for your mistake.
Using "if" fails to take the consequences of your mistake seriously.
This apology makes excuses and fails to take responsibility.

Sticking to the structure "I am sorry that I ... It was my responsibility to ..." ensures you won't make bad apologies.

Which apology statement is better?