15. Below is an internal control associated with some financial statement audit cycle that the auditors identified for one of their clients. Indicate the control activity that is being considered in this case. "The general ledger accounts receivable control account is reconciled against the accounts receivable subsidiary monthly."

a. to Segregation of tasks (adequate separation of duties)

b. Independent check on performance

c. Physical controls over assets and records (physical controls)

d. Adequate documents and records and records)