Choose the underlined part that needs correction in the following question

Once you can overcome your difficulty, the problems may well become a source of strengthen to your marriage and to your faith.

Choose the word whose underlined part differs from the other three in pronunciation in the following question.

Choose the word whose underlined part differs from the other three in pronunciation in the following question.

Choose the word whose underlined part differs from the other three in pronunciation in the following question.

Choose the word that differs from the other three in the position of primary stress in the following questions.

Choose the word that differs from the other three in the position of primary stress in the following questions.

Choose the underlined part that needs correction in the following question

He is too old joining this event.