It is difficult to determine whether elderly people are being denied care under Medicaid because:

a$.$ funding for Medicaid is under the control of private firms in the United States.

b$.$ states set different income limits to determine the eligibility for Medicaid.

C$.$ most elder people opt for Medicare instead of Medicaid.

d$.$ Medicaid is the least popular source of long$-$term care for the elderly and disabled.