Shanghai Cooperation Organization (SCO) has 4 observer states which are:
(a) Iran, Mongolia, Sri Lanka, Turkey
(b) Afghanistan, Nepal, Belarus, Azerbaijan
(c) Iran, Afghanistan, Belarus, Turkey
(d) Iran, Afghanistan, Belarus, Mongolia
(a) Iran, Mongolia, Sri Lanka, Turkey
(b) Afghanistan, Nepal, Belarus, Azerbaijan
(c) Iran, Afghanistan, Belarus, Turkey
(d) Iran, Afghanistan, Belarus, Mongolia