In an Economy as Complex as Ours,the Only Way to Achieve

In an economy as complex as ours,the only way to achieve a meaningful estimate of what we produce is to

A) reduce everything to a common denominator: money.
B) consider the number of hours of labor involved in production.
C) calculate the ultimate value of each product to our social welfare.
D) count only tangible products, not intangible services.
E) aggregate all financial transactions for a given year.