Which of the following statements is incorrect?

a$.$ Of the three levels of planning, corporate strategy is the broadest.

b$.$ Business$-$unit strategy should be consistent with the corporate strategy.

C$.$ Marketing strategy should be consistent with both the business$-$unit and corporate strategies.

d$.$ Strategic planning begins at the marketing level and proceeds through business$-$unit and corporate levels.

e$.$ Strategic planning begins at the corporate level and proceeds through business$-$unit and marketing levels.