Table schema:
CREATE TABLE table_name_54 (frequency_mhz VARCHAR, erp_w VARCHAR, class VARCHAR, call_sign VARCHAR)

Question: Name the total number of frequency Mhz with class of d and call sign of k201bm and ERP W less than 74
SQL: SELECT COUNT(frequency_mhz) FROM table_name_54 WHERE class = "d" AND call_sign = "k201bm" AND erp_w < 74