Social Security Payments by the Government Are NOT Included in GDP

Social Security payments by the government are NOT included in GDP because

A) Social Security was not yet in place when procedures for calculating GDP were devised.
B) Social Security is counted as an economic cost and subtracted from output in determining GDP.
C) income received through Social Security is not directly related to contributions to production.
D) income received through Social Security is too small to affect GDP.
E) these payments are in current dollars and GDP is measured in constant dollars.