(i) Boron reacts with concentrated $HNO_3$ to form nitric oxide and boric acid
(ii) Boron reacts with fused $NaOH$to form $H_2O_2$ and boric acid
(iii) Boron reacts with $SiO_2$ to form $Si\: and \: B_2O_3$
$\begin {array} {1 1} (1)\;(i),(ii) \: and \: (iii) & \quad (2)\;(i) \: and \: (iii) \\ (3)\;(ii)\: and \: (iii) & \quad (4)\;(i)\: and \: (ii) \end {array}$
