A car changing its speed from $0$ to $20\frac{m}{s}$ at a constant rate in $1$ second has an average acceleration of $q,$

$q,$

$0\frac{m}{s^2}$

$10\frac{m}{s^2}$

$-20\frac{m}{s^2}$

$20\frac{m}{s^2}$