Which phrase is grammatically incorrect in the following sentence? The most important things in my life are making money, traveling abroad, and to live well.

The correct choice is B: 'To live.' The original sentence is grammatically incorrect as it should read 'and living well,' instead of 'to live well.' In this context, 'living well' is the correct phrase to describe a desired lifestyle, as opposed to 'to live well,' which is not grammatically appropriate in this sentence. The sentence structure 'making money, traveling abroad, and living well' showcases a list of important things in the speaker's life, with 'living well' serving as one of the key aspects alongside making money and traveling abroad.