The president cannot be chief justice - this would be a breach of the separation of powers. Chief Justice is a member of the judicial branch of the government; and the president is the head of the executive branch of the government, so they should not be the same person - the answer is d)
The lowest price proposals shouldn't be always picked as a winner even if it costs lowly because the individual responsible for the decision should take other matters into consideration and whether what are the right decisions that he or she should make for the betterment of the company. Example of this is the lowest price materials offered by one contractor in which it is cheap but is not as strong as other materials they often buy, the one responsible of taking this account should ensure whether it is even right to use as their materials when he or she knows that it is not as strong as the ones they often used.
Their were no official vice president candidates in the election of 1800