This is for a review not a test.
what would n be? i don’t really understand how to find it.

The needed electrons, N = 4 for silicon (Si)

and N = 1 for chlorine (Cl).

Explanation:

Si has atomic number 14 and belongs to group 14  and 3 period.

The electronic configuration of Si is 1s²2s²2p⁶3s²3p².

so, there are 4 electrons in valence shell i.e) third shell (n=3)

so, according to Lewis it needs 4 more electrons to get stability via octet configuration.

Cl has atomic number 17 and belongs to group 17 and 3 period.

The electronic configuration of Cl is 1s²2s²2p⁶3s²3p⁵.

so, there are 7 electrons in valence shell i.e) third shell (n=3)

so, according to Lewis it needs 1 more electrons to get stability via octet configuration.

So, in order to get stability 4 Cl atoms form 4 covalent bonds with 1 Si atom

In a Covalent bond, electrons are shared. so, now both Si and Cl have octet configuration.

the answer would be a