Correct answers: Ich trinke einen Apfelsaft. Ich trinke Apfelsaft. Apfelsaft trinke ich. There are some situations, when this answer would be correct, but in 99% of the cases one would chose one of the two above answers.

I am doing some exercise, and the answer from the answer book is the second one 'Apfelsaft trinke ich'. So I am confused. thank you.

Who says that "ich trinke Apfelsaft" is wrong?