Do it have a text to read or something like that?
Traiga el pan Ud.
Why?
B) Trae could be correct, but it's present tense, not future tense.
C) Traen is past present tense, not future tense.
D) Traigan is for a group, here it's only one person, Ud.
This is how we get A) Traiga, because we use the present tense and the one-person word.
Hope this helps!~
—A quince which is held for birthdays! family comes to celebrate and bring gifts and there’s a bunch of music dancing and entertainment!
—Día de los Muertos! A celebration of the dead to respect and welcome their spirits!