The cause of sweet taste in fruits is:

Correct answer: (d) Fructose

Explanation

Fructose is a natural fruit sugar and the sweetest of the common sugars, giving ripe fruits their sweet taste.

Sweetness rises with higher sugar content (fructose, glucose, sucrose) in the fruit.

Maltose and lactose are far less sweet, and ribose is a structural sugar of nucleic acids.