Diborane reacts with ammonia under different conditions to give a variety of products. Which one among the following is not formed in these reactions ?

Question

$$\begin {array} {1 1} (1)\;B_2H_6.2NH_3 & \quad (2)\;B_{12}H_{12} \\ (3)\;B_3N_3H_6 & \quad (4)\;(BN)_n  \end {array}$$