Tautomerism is exhibited by

$(a)\;(i),(ii) and \;(iii) \\ (b)\;(i),(iii) and \;(iv) \\ (c)\;(ii),(iii) and (iv) \\ (d)\;(i),(iii) and (iv)$

Tautomerisum is exhibited by (i),(iii) and (iv)
Hence b is the correct answer.