What are the main types of organic reactions and their mechanisms?

Match the reactions in column $I$ with appropriate types of steps/reactive intermediate involved in these reactions as given in column $II$.
| Column $I$ | Column $II$ |
| :--- | :--- |
| $(A)$ $1-$phenylpentane$-1,4-$dione $\xrightarrow{aq. NaOH}$ $3-$phenylcyclopent$-2-$en$-1-$one | $(p)$ Nucleophilic substitution |
| $(B)$ $4-$chloro$-1-$phenylbutan$-1-$one $\xrightarrow{CH_3MgI}$ $2-$methyl$-2-$phenyltetrahydrofuran | $(q)$ Electrophilic substitution |
| $(C)$ $4-$hydroxy$-1-$phenylbutan$-1-$one $\xrightarrow{H_2SO_4}$ $2-$phenyl$-4,5-$dihydrofuran | $(r)$ Dehydration |
| $(D)$ $4-$methyl$-4-$phenylpentan$-1-$ol $\xrightarrow{H_2SO_4}$ $1,1-$dimethyl$-1,2,3,4-$tetrahydronaphthalene | $(s)$ Nucleophilic addition |
| | $(t)$ Carbanion |

In a reaction,if half of the double bond is broken and two new bonds are formed,this is a case of

What is the fission of a covalent bond? Explain its types with examples and the main differences.

Which statement is correct for the given reactions?

In the above reaction,the electrophile is substituted at the meta position only,due to:
$I$. Electron density is more at ortho $\&$ para positions
$II$. Electron density is relatively less at ortho $\&$ para positions
$III$. Electron density is less at meta position
$IV$. Electron density is relatively more at meta position
The correct answer is: