The aromatic carbocation among the following is

Cyclic hydrocarbon molecule $A$ has all the carbon and hydrogen atoms in a single plane. All the carbon-carbon bonds are of the same length and are less than $1.54 \ \mathring{A}$ but more than $1.34 \ \mathring{A}$. The $C-C-C$ bond angle will be:

Benzene on treatment with a mixture of conc. $HNO_3$ and conc. $H_2SO_4$ at $90^\circ C$ gives :

In the Friedel-Crafts reaction,anhydrous $AlCl_3$ is used because...

The non-aromatic compound among the following is

Given below are two statements. One is labelled as Assertion $A$ and the other is labelled as Reason $R$.
Assertion $A$: $[6]-$Annulene,$[8]-$Annulene and cis$-10-$Annulene are respectively aromatic,non-aromatic and non-aromatic.
Reason $R$: Planarity is one of the requirements of aromatic systems.
In the light of the above statements,choose the most appropriate answer from the options given below.