The strongest base among the following is :

The correct order of basicity in amines is $2^0>1^0>3^0$

Here, ${\left(C_6{H}_5\right)}_{2}NH$ and ${\left(C_2{H}_5\right)}_{2}NH,$ both are $2^0$ amines but ${\left(C_2{H}_5\right)}_{2}NH,$ is more basic because it has no conjugation where as in ${\left(C_6{H}_5\right)}_{2}NH$ conjugation is present.