Subject to subsection (b) of this section, to renew a license, a license holder shall file a license renewal application with the Board in accordance with the following schedule of renewal deadlines and license expiration dates: for a Class A license, which shall expire on April 30, the application deadline is March 1; for a Class B license, which shall expire on May 31, the application deadline is April 1; and for a Class C and a Class D license, both of which shall expire on June 30, the application deadline is May 1. The Board may extend the deadline by which a license holder must file a license renewal application.