The argument is that the government's calculation is inaccurate and needs to be changed.
This is largely supported by the fact this calculation only takes into account cash income, not capital gains/ non-cash benefits.
We are then asked to validate this argument
A is incorrect - it actually provides grounds that the calculation is reasonably accurate
B is incorrect - i don't see how this is conducive to the contention as we are comparing one crappy calculation to another.
C is correct as it provides multiple pieces of evidence ("most...studies") that highlights the difference in question
D is incorrect - it is completely beside the point. We want to highlight that the current calculating is wrong, not that another calculation is better.
E is incorrect as it merely tells us information already known and presented in the argument.
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