The distance $d$ between two points $P_1=(x_1,y_1)$ and $P_2=(x_2,y_2)$ is $d=$

The distance $d$ between two points $P_1=(x_1,Y_1)$ and $P_2=(x_2,Y_2)$ is

$\sqrt[\phantom{2}]{(x_2{y}_2{)}^2(x_1{y}_1{)}^2}$

$\sqrt[\phantom{2}]{(x_2-y_2{)}^2(x_1-y_1{)}^2}$

$\sqrt[\phantom{2}]{(x_2-x_1{)}^2(y_2-y_1{)}^2}$

$\sqrt[\phantom{2}]{(x_2{x}_1{)}^2(y_2{y}_1{)}^2}$