Explanation : S1 is total number of modules defined in the program architecture. S2 is total number of modules whose correct function depends on the source of data input or that produces data to be used elsewhere. S3 is the number of modules whose correct function depends on prior processing. Program structure (D1) is defined as if architectural design was developed using a distinct method then D1 is 1 otherwise it is zero. Module independence: D2 = 1 - (S2 / S1) Module not dependent on prior processing: D3 = 1 - (S3 /S1) So, option (B) is correct.