The reaction among the following that proceeds through an electrophilic substitution reaction is:

1.
2.
3.

4.

In the following reaction,

\( CH_{3}C\equiv CH\xrightarrow[Red \ hot \ iron \ tube]{873 K} \ A\)

The number of ($\sigma$) bonds present in the product (A) is:

1. 21 

2. 9

3. 24

4. 18