input: Text: Bread Overhead By FRITZ LEIBER The Staff of Life suddenly and disconcertingly sprouted wings —and mankind had to eat crow! Illustrated by WOOD AS a blisteringly hot but guaranteed weather-controlled future summer day dawned on the Mississippi Valley, the walking mills of Puffy Products ("Spike to Loaf in One Operation!") began to tread delicately on their centipede legs across the wheat fields of Kansas. The walking mills resembled fat metal serpents, rather larger than those Chinese paper dragons animated by files of men in procession. Sensory robot devices in their noses informed them that the waiting wheat had reached ripe perfection. As they advanced, their heads swung lazily from side to side, very much like snakes, gobbling the yellow grain. In their throats, it was threshed, the chaff bundled and burped aside for pickup by the crawl trucks of a chemical corporation, the kernels quick-dried and blown along into the mighty chests of the machines. There the tireless mills ground the kernels to flour, which was instantly sifted, the bran being packaged and dropped like the chaff for pickup. A cluster of tanks which gave the metal serpents a decidedly humpbacked appearance added water, shortening, salt and other ingredients, some named and some not. The dough was at the same time infused with gas from a tank conspicuously labeled "Carbon Dioxide" ("No Yeast Creatures in Your Bread!"). Thus instantly risen, the dough was clipped into loaves and shot into radionic ovens forming the midsections of the metal serpents. There the bread was baked in a matter of seconds, a fierce heat-front browning the crusts, and the piping-hot loaves sealed in transparent plastic bearing the proud Puffyloaf emblem (two cherubs circling a floating loaf) and ejected onto the delivery platform at each serpent's
  Question: What made Roger decide to sell Puffyloaves like balloons?
  
   (A) Shipping constraints
   (B) Government regulation
   (C) Cheaper packaging materials
   (D) Children's demands of their parents
  Answer:
output: Children's demands of their parents