What did Franklin Roosevelt do when the Supreme Court struck down several key pieces of New Deal legislation? A.

Roosevelt accused the Supreme Court justices of malpractice and overreaching their authority.

B.

Roosevelt successfully added more Supreme Court justices to the bench that supported his policies.

C.

Roosevelt failed at a "court packing" plan but persuaded the Supreme Court justices to support his programs.

D.

Roosevelt lobbied for certain justices to be replaced after they challenged New Deal legislation.

B.

Roosevelt successfully added more Supreme Court justices to the bench that supported his policies.

Explanation:

During the time of Franklin Roosevelt as the President of the United States, when Supreme Court struck down several key pieces of his New Deal legislation, after two years, he first proposed age limit for Justices, such that whenever a Justice clock 70 years, and 6 months old, and who had served 10 years or more should be retired.

However, should a Justice refuse to retire, Roosevelt added More Supreme Court Justices to the bench, with equal voting right. This was later termed as "Court parking".

Hence, the right answer is, Roosevelt successfully added more Supreme Court justices to the bench that supported his policies.