The correct option is A feet
From the given options, gallons are used for measuring the capacity and ounces are used to measure the weight of any object/person.
Miles and feet are units of length.
Mile is the larger unit while feet is the smaller unit.
Dining table is not so long to be measured in miles.
Hence, smaller unit will be used to measure the length of the table.
So, feet is the appropriate unit to measure the length of a dining table.