Answer:
A. a president is more likely to appoint judges who would agree with him ideologically.
Step-by-step explanation:
According to the Constitution, it is President who nominates judges for federal courts and the Supreme Court. After the nomination, it is Senate who appoint them based on informal criteria, as there's no criteria mentioned in the Constitution.
The most likely reason that appointment of judges by President is blocked is because the president is appointing judges who would agree with him ideologically. The Senate will block such nominations to ensure that judges who are appointed judge with justice and not under any influence from any political power.
Therefore, option A is correct.