(a) True - The context clearly states that 'the non-permanent members do not have the veto power' and 'The main privileges of the five permanent members are permanency and the veto power.'

(b) True - The context explains that 'the permanent members can vote in a negative manner so that even if all other permanent and non-permanent members vote for a particular decision, any permanent member's negative vote can stall the decision. This negative vote is the veto.' It is explicitly called a 'negative vote.'

(c) False - The context does not attribute veto power to the Secretary-General. The veto power belongs exclusively to the five permanent members of the Security Council. The Secretary-General is not mentioned as having any veto authority.

(d) True - The context states that 'any permanent member's negative vote can stall the decision.' This means a single veto is sufficient to block or stall a Security Council resolution.