Out of following isomeric forms of uracil, which one is present in RNA?

Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R).

Assertion (A) : Synthesis of ethyl phenyl ether may be achieved by Williamson synthesis.

Reason (R) : Reaction of bromobenzene with sodium ethoxide yields ethyl phenyl ether.

In the light of the above statements, choose the most appropriate answer from the options given below :

In the following sequence of reactions the P is :

The unit of the van der Waals gas equation parameter 'a' in $$\left( {P + {{a{n^2}} \over {{V^2}}}} \right)(V - nb) = nRT$$ is :