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 :

In polythionic acid, H₂S_xO₆ (x = 3 to 5) the oxidation state(s) of sulphur is/are :