GInI's framework for innovation engagement includes rewards as a reinforcement mechanism, typically categorized as tangible incentives like 'cash prizes' or 'high-value material prizes.' These are highlighted in the CInP Handbook as effective motivators for participation. 'Promotions / salary raises' (B) and 'letters of appreciation / certificates of accomplishment' (C) might be used in some contexts, but GInI specifies tangible rewards as the primary focus. 'New cars / vacation homes' (D) is an exaggerated distractor not aligned with standard practice. The question's phrasing confirms A as the intended answer.