Which of the following statement is correct?

1. Geometrical isomerism is not observed in complexes of coordination number 4 having tetrahedral geometry.

2. Square planar complexes generally do not show optical isomerism.

3.Mabcd can have three geometrical isomers.

4. ${\left[Pt\left(gly\right){}_3\right]}^{+}$ can exibit both geometrical and optical isomerism.