Which of the following pairs of the compounds may be regarded both as functional group isomer and position isomer?

What is the tautomer of 'II' structure from the following?

Which of the following statements is false regarding the enolization of

$\left(\mathrm{a}\right)$ It can form two types of enolic forms of equal stability.

$\left(\mathrm{b}\right)$ It can form two types of enolic forms of different stability.

$\left(\mathrm{c}\right)$ It can form more than two types of enolic forms of different stability.

$\left(\mathrm{d}\right)$ It can form only one type enolic form.

Keto-enol tautomerism is observed in

(a) 

(b) 

(c)    

(d)      

If ${\mathrm{D}}^{+}$ is catalyst. What is the compound $\mathrm{A}$?

What is the maximum number of geometrical isomers possible for the following compound?