A. he comes on feet.
b. he comes on foot.
which one why?

He comes on foot.
He comes on foot because “foot” is a singular form for you’re walking with your own feet.
“Feet” would be plural as in more than one pair of feet.

I hope I answered your question the way you asked. If not let me know, I’ll try to answer the question to what you’re looking for.

answer: military leaders, supporters of the confederacy and supporters of the union.

explanation:

on november 19, 1863, the speech delivered by president abraham lincoln, known as 'gettysburg address', was intended for politicians, military officials, notable citizens as well as general public, and members of the press who had gathered for the ceremony held in gettysburg, pennsylvania. this ceremony was being celebrated since, in that same year, the battle of gettysburg took place in rural pennsylvania, leaving thousands of men, both union and confederate, killed. lincoln argued about equality within the nation, and the purpose of the war being a "new birth of freedom."on the other hand, there is no relation between lincoln's gettysburg address and his son.