Choice "A" is correct. Decision support systems (DSS) are computer-based information systems that provide interactive support to managers or others during the decision-making process. Transaction processing systems process data resulting from business transactions (monthly, historical in nature; not predictive).
Choice "c" is incorrect. A financial modeling application is a DSS to assist management in evaluating financing alternatives.
Choice "d" is incorrect. Database query applications are a DSS that read and reorganize data to management's specifications but do not allow alterations of the data.
Choice "b" is incorrect. Sensitivity analysis is a DSS that uses a "what if" technique that asks how a given outcome will change if the original estimates of the model are changed.