Correct Answer - b
i`CuSO_(4) + BaCI_(2) rarr BaSO_(4) darr + 2HCI`
`ii 2CuSO_(4)+4KI to 2K_(2)SO_(4)+underset("white ppt.")(CuI_(2)+I_(2)darr`
`I_(2)+2Na_(2)S_(2)O_(3)to 2NaI+Na_(2)S_(4)O_(6)`
`(iii) 2Cu^(2+)+K_(4)[Fe(CN)_(6)]to underset("ppt.")underset("(chocolate)")underset("Red-brown")`