If your parents are wrong and you're right what shall you do?
If you are convinced that you are right and your parents are wrong, then you owe it to them to point out their mistakes, but do so with utmost respect.
The fact that your parents are wrong does not give you the right to act arrogantly or rudely towards them. Remember Allah ordered His Messengers, Mosa and Harun, to speak to Pharoah in a gentle manner--in spite of the fact that the latter was a tyrant. "Go to Pharoah, for verily he has transgressed all bounds, but speak to him with gentle words, that perhaps he may take warning, or fear (Allah)." (Qur'an: 20: 43-44)
And while reminding the children of their duties towards parents, Allah says, " Your Lord has ordained that you shall worship none but Him. And do good unto [thy] parents. Should one of them, or both, attain to old age in thy care, never say "Ugh" to them or scold them, but [always] speak unto them with reverent speech..." (Qur'an: 17: 23).