Answer: The politicians have been discussing the social program for the last month.
Explanation: The present perfect progressive tense is mainly used to refer to an action or event that started in the past and continues in progress at present. This tense is formed with the verb "have" or "has" plus "been" plus the present participle of a verb. Moreover, the present participle of a verb always ends in -ing. In that way, the present perfect progressive form of the verb "discuss" is "have been discussing" ("discussing" is the present participle of "discuss").