Group `13` element reacts with halogen and forms a compound P shows the following properties:
(i) It is white solid and exist as dimer, gives fumes of Q with moist air
(ii) It sublimes on `180^(0)C` and forms monomer if heated to `400^(@)C`
(iii) Its aq solution turns blue litmus to red
(iv) Addition of `NH_(4)OH` and `NaOH` separately to a solution of P gives white precipitate which is however soluble in excess of `NaOH` solution to form a solution R
Anionic formula of solution R is :
A. `[B(OH)_(6)]^(3-)`
B. `[Al(OH)_(4)(H_(2)O)_(2)]^(-)`
C. `[Al(OH)_(6)]^(3-)`
D. `[Al(OH)_(5)]^(3-)`
