The correct option is B A and B
The President can withhold assent to an Ordinary Bill indefinitely. If no political party or leader has majority support in the Lok Sabha, the President has the freedom to decide who should be appointed as Prime Minister. Further, if the Prime Minister loses the confidence of the Lok Sabha, the President can decide whether the Lok Sabha should be dissolved, or if an alternate government should be formed.
However, the appointment of ministers is done on the advice of the Prime Minister, and is not a discretionary power.