A machine makes two components; call them types A and B$.$ It takes $250$ seconds to switch production between the component types. During that time, no production occurs. When in production, each unit of $A$ or $B$ requires $0\mathrm{.}5$ second to be completed. The two components, A and $B,$ are combined in an assembly process to make a final product; call it $C.$ The assembly step can combine the two components into $1$ unit every $1\mathrm{.}25$ seconds. Suppose the machine rotates between one batch of $1000$ units of A and $1000$ units of $B.$ What is the utilization of the machine?

$80\%$

$60\%$

$50\%$

$70\%$