Correct option is C
Statement 1 is correct.
Pushyamitra Shunga was a military commander (Senapati) under the last Mauryan ruler, Brihadratha. He assassinated Brihadratha during a military parade and subsequently established the Shunga dynasty, marking the end of the Mauryan Empire.
Statement 2 is incorrect.
While Pushyamitra Shunga did perform Ashvamedha sacrifices to assert his sovereignty and legitimacy, the number of sacrifices is not definitively stated as twenty. The historical accounts and texts like the "Divyavadana" mention that he performed Ashvamedha sacrifices, but they do not specify that he performed twenty such rituals after defeating the Yavanas (Indo-Greeks).