Correct Answer - D
(I)No colour in flame test (Be)
BeO is Amphoteric oxide in nature
`(BeH_2)_n`
electron deficient and polymeric
(II)Violet colour in flame test ( K Metal)
`KO_2`(Potassium super oxide ) is orange yellow
`KO_3`(Potassium ozonide) is orange-red solid
(III)yellow colour in flame test (Na metal)
`Na_2CO_3`(sodium carbonate ) is manufactured by solvay process
microcosmic salt `to Na(NH_4)HPO_4. 4H_2O`