k+HgCl2 gives u Hg+ KCl

2K + HgCl2 —> Hg + 2KCl

Explanation:

K + HgCl2 —> Hg + KCl

The above equation is not balanced

To balance the equation, do the following.

First, put 2 in front of KCl, the equation becomes,

K + HgCl2 —> Hg + 2KCl

Now we see that Cl is balanced but K is not. To balance K, put 2 in front of K as shown below:

2K + HgCl2 —> Hg + 2KCl

Now we can that the equation is balanced

the answer would be a