The products $(A)$ and $(B)$ of the above reaction are:

The major product $(C)$ is

The major product in the following reaction is

Identify the mechanism of the following reaction:

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:

Which different types of reaction mechanisms are observed in addition reactions?