The Shunga Dynasty had made _________ the official religion of their kingdom.
A)Buddhism
B)The Ajivika Sect
C)Jainism
D)Brahmanism

Hint :
The Shunga Empire was an ancient Indian dynasty from Magadha that controlled areas of the central and eastern Indian subcontinent from around 185 to 75 BCE.The Pushyamitra Shunga (185 – 149 BC ) was the founder of this Empire. He was the first ruler and prosecutor of Buddhists.

Complete answer :
The Shunga dynasty replaced the Mauryan dynasty, the last Mauryan ruler was assassinated by Brihadratha at a military parade.Several campaigns was also conducted by Pushyamitra against Yavanas, Indo-Greeks as they were trying to expand from the Bacteria into the north western India during that period.
Pushyamitra ruled the kingdom for about 36 years and his successor was Shunga, but the history after Pushyamitra is uncertain and nothing substantial is known about his successors.
If the Puranic account is believed then, the total tenure of the Shunga rule is about 112 years which came to end in 73 BCE.
The Shunga period was known for its visual arts which includes small terracotta images, flowering, large stone sculptures and architectural monuments such as the stupa at Bharhut, chaitya hall at bhaja and the renowned Great stupa at Sanchi.
Under the Shunga patronage, the core of the Great Stupa was enlarged to a diameter of 120 feet, it was covered with a stone casing and was decorated with the images of fertility spirits.

Thus, the option (D) is correct.

Note :Pushyamitra was a Brahmin and he is said to have prosecuted Buddhists, this was the reason why Buddhism flourished in many areas during his rule. He ruled the cities of Vidisha, Ayodhya (Oudh), Pataliputra, Jalandhra and Shakara.