Let us consider an endothermic reaction which is non-spontaneous at the freezing point of water. However, the reaction is spontaneous at boiling point of water. Choose the correct option.

Which of the following arrangements with respect to their reactivity in nucleophilic addition reaction is correct?

The carbohydrate "Ribose" present in DNA, is

A. A pentose sugar

B. present in pyranose from

C. in "D" configuration

D. a reducing sugar, when free

E. in $\propto$-anomeric form

Choose the correct answer from the options given below:

Aman has been asked to synthesise the molecule He thought of preparing the molecule using an aldol condensation reaction. He found a few cyclic alkenes in his laboratory. He thought of performing ozonolysis reaction on alkene to produce a dicarbonyl compound followed by aldol reaction to prepare " $x$ ". Predict the suitable alkene that can lead to the formation of " $x$ ".