Insert the missing words (they apply to both sentences):

We may feel pressured into conceding that long-term planning must establish formal terms of reference for these planned audits. Fortunately, the . . . . . . . . . . . . . . . . . comes to the rescue since we need not provide detailed plans for each audit over and above the act of selecting those areas that attract a high level of risk. The . . . . . . . . . . . . . . . . . allows us to take an audit area and carry out some background work with a view to setting formal terms of reference for the ensuing audit.

a. preliminary survey

b. audit plan

c. risk management

d. terms of reference