Which of the following is an example of homoleptic complex ?

Question

$\begin{array}{1 1}(1)\; [Co(NH_3)_6]Cl_3 \\ (2)\; [Pt(NH_3)_2Cl_2] \\ (3)\; [Co(NH_3)_4Cl_2] \\ (4)\; [Co(NH_3)_5Cl]Cl_2 \end{array} $