Which of the following equimolar mixtures is known as invert sugar?

Glucose and fructose form:

Match the structures in Row $I$ with their names in Row $II$.
Row $I$:
$(P)$ $\alpha-D-(+)-$Glucopyranose
$(Q)$ $\beta-D-(+)-$Glucopyranose
$(R)$ $\alpha-D-(-)-$Fructofuranose
$(S)$ $\beta-D-(-)-$Fructofuranose
Row $II$:
$(i)$ $\alpha-D-(-)-$Fructofuranose
$(ii)$ $\beta-D-(-)-$Fructofuranose
$(iii)$ $\alpha-D-(+)-$Glucopyranose
$(iv)$ $\beta-D-(+)-$Glucopyranose
Correct match is:

The correct corresponding names of the four aldoses with the configurations given below,respectively,are:

Glycosidic linkage between $C_{1}$ of $\alpha$-glucose and $C_{2}$ of $\beta$-fructose is found in.

The following carbohydrate is