Given the following crontab entry, when will the job run?
30 5 * 9 * /usr/local/bin/maintenance

A.
Every day in September at 05.30

B.
Every day at 05.00 and 09.00 for 30 days

C.
Every 30 minutes for the first 5 days in September

D.
Only on the 30th of May in 9 minute intervals

Explanation:
Reference: http://www.adminschoice.com/crontab-quick-reference