In a certain code language, "851" means "good sweet fruit", "783" means "good red rose", and "341" means "rose and fruit". Which of the following digits stands for "sweet" in that language?

Explanation

Compare the three codes:
851 = "good sweet fruit"
783 = "good red rose"
341 = "rose and fruit"
From the overlaps, 8 = good, 1 = fruit, and 3 = rose. The unused digit in 851 is therefore 5 = sweet.