According to the Kaiser Family Foundation's Employer Health Benefits survey 2020, despite of or because of continued increases in healthcare premium costs

a. the percentage of firms offering health benefits that are self-funded is increasing

b. the percentage of covered works that enroll in HMO plans is increasing

c. the percentage of firms offering health benefits that are self-funded is decreasing

d. the percentage of workers that have no claims under the plan during the year is increasing