(a) Payment of the tax covering the initial period is due within 90 days after the date that the initial period ends or, if applicable, within 91 days after the date of the merger.
(b) Payment of the tax covering the second period is due on the same date as the tax covering the initial period.

(c) Payment of the tax covering the regular annual period is due May 15, of each year after the beginning of the regular annual period. However, if the first anniversary of the taxable entity’s beginning date is after October 3 and before January 1, the payment of the tax covering the first regular annual period is due on the same date as the tax covering the initial period.