Which cube is a unit cube? a cube that is 5 meters long, 5 meters wide, and 5 meters high

a cube that is 2 feet long, 2 feet tall, and 2 feet high

a cube that is 3 yards long, 3 yards wide, and 3 yards high

a cube that is 1 inch long, 1 inch wide, and 1 inch high

Oscar and julie ashton are celebrating their 15th anniversary by having a reception hall. they have budgeted $4,500 for their reception. if the reception hall charges a $90 cleanup fee plus & 36 per person, find the greatest number of people that they may invite and still stay within their budget.