Right choice is (a) Single-stage
Best explanation: Single-stage tendering is the more traditional route, used when all the information necessary to calculate a realistic price is available when tendering commences:
• An invitation to tender is issued to prospective suppliers (perhaps following completion of a pre-qualification questionnaire and/or a pre-tender interview). The invitation to tender will include information describing the goods or services required in sufficient detail to enable prospective suppliers to prepare an accurate tender.
• Tenders are prepared and returned by prospective suppliers (this may involve questions and answers and a mid-tender interview to clarify the client’s requirements).
• Submitted tenders are then assessed and compared (this may involve further interviews).
• The preferred tenderer is selected and negotiations opened.
• Subject to the outcome of those negotiations the preferred tenderer may then be appointed.