Rochelle salt is a dimetal salt of:

Given below are two statements :
Statement $I :$ $D$-glucose pentaacetate does not react with $2,4$-dinitrophenylhydrazine.
Statement $II :$ Starch,on heating with dilute sulfuric acid at $393 \ K$ and $2-3 \ \text{atmosphere}$ pressure,produces glucose.
In the light of the above statements,choose the correct answer from the options given below.

Glucose on oxidation with bromine water yields gluconic acid. This reaction confirms the presence of $-$

An invert sugar is

What are reducing sugars?

$D$-Mannose $\overset{HO^{-}}{\longleftrightarrow}$ $D$-Glucose $\overset{HO^{-}}{\longleftrightarrow}$ $(A)$.
Product $(A)$ of the above reaction is: