How can you say that glucose is a cyclic compound?

Given below are two statements:
Statement $I$: The two cyclic forms of $D-(+)-glucose$ ($\alpha$ and $\beta$ anomers differing at $C1$ hydroxyl orientation) are two anomers of $D-(+)-glucose$.
Statement $II$: The open chain forms of $D-glucose$ and $D-fructose$ contain three similar chiral carbons at $C3$, $C4$, and $C5$.
In the light of the above statements, choose the correct answer from the options given below:

The synthetic detergent used in toothpaste is of type $X$. Animal starch is $Y$. $X$ and $Y$ respectively are:

Which of the following is $NOT$ correct about fructose?

Which one is a disaccharide?

The configurations of the chirality centres in $D$-threose (shown) are