Four students studied reactions of zinc and sodium carbonate with dilute hydrochloric acid and dilute sodium hydroxide solutions and presented their results as follows. The (↑) shows evolution of gas and (−) shows no reaction. The right set is :
(a)

	Zn	Na2CO3
HCl	✔	✔
NaOH	✔	✔

(b)

	Zn	Na2CO3
HCl	─	✔
NaOH	✔	✔

(c)

	Zn	Na2CO3
HCl	✔	✔
NaOH	✔	─

(d)

	Zn	Na2CO3
HCl	✔	─
NaOH	✔	✔