A polynomial $P(x)=c_{2020}{x}^{2020}+c_{2019}{x}^{2019}+\dots +c_{1}x+c_0$ has real coefficients with $c_{2020}\ne 0$ and $2020$ distinct complex zeroes $z_k=a_k+b_{k}i$, $1\le k\le 2020$ with $a_k$ and $b_k$ real. Given that no root is zero, one of the roots is $1$, one of the roots is $2$, and ${\sum }_{k=1}^{2020}{a}_k=0$. Which of the following quantities can be a nonzero number?