There are 222 single employees in job grade 2, and 3,927 married employees in job grade 2. which is higher, the conditional relative frequency among single employees in grade 2, or among married employees in grade 2?           a. joint frequency   b. conditional relative frequency   c. married and grade 2 (92.6%) is higher than single and grade 2 (5.2%)   d. single and grade 2 (65.9%) is higher than married and grade 2 (50.8%)