Identify A and B in the following reaction sequence.

Match List I with List II

Choose the correct answer from the options given below:

Given below are two statements :

Statement I : Aniline reacts with con. $$\mathrm{H}_2 \mathrm{SO}_4$$, followed by heating at $$453-473 \mathrm{~K}$$ gives $$\mathrm{p}$$-aminobenzene sulphonic acid, which gives blood red colour in the 'Lassaigne's test'.

Statement II : In Friedel - Craft's alkylation and acylation reactions, aniline forms salt with the $$\mathrm{AlCl}_3$$ catalyst. Due to this, nitrogen of aniline aquires a positive charge and acts as deactivating group.

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

A sample of $$\mathrm{CaCO}_3$$ and $$\mathrm{MgCO}_3$$ weighed $$2.21 \mathrm{~g}$$ is ignited to constant weight of $$1.152 \mathrm{~g}$$. The composition of mixture is :

(Given molar mass in $$\mathrm{g} \mathrm{~mol}^{-1} \mathrm{CaCO}_3: 100, \mathrm{MgCO}_3: 84$$)