Answer:
c. 2,2-dichloropentane.
Explanation:
Hello there!
In this case, according to the given information, it turns out possible for us to firstly draw the structure of the reactant, pent-1-yne:

Now, we infer the halogen is added to the carbon atom with the most carbon atoms next to it, in this case, carbon #2, in order to write the following product:

Whose name is 2,2-dichloropentane.
Regards!
The metalloids are Boron, Silicon, Geranium, etc and are found to the right of the metals and the left of the nonmetals. Since that is not an option, the best choice would be: The metalloids are located below nonmetals and above metals within a group.
Answer: only Br2.
Justification.
In a chemical reaction the element that gains electrons experiments a reduction in its oxidation state, that is why it is said that it is reduced.
So, to know what element is being reduced you need to calculate the oxidation states of the elements involved.
Here I indicate the oxidation states of each element if the reaction putting them inside parenthesis:
Reactants side Products side
K (0) K (1+)
Br (0) Br(1-)
So, K lost one electron, increasing its oxidation statefrom 0 to 1+, meaning that it is being oxidized.
And, each atom of Br gained one electron, reducing its oxidation state from 0 to 1-, meaning it is being reduced.
Therefore, the answer is that Br2 is the substance being reduced.