Which is the BEST description of the effect that the "Baby Boom" had on the American economy?

is this a multiple choice question? if so, could i see the answers to give you the right one!

crop rotation kepy different plants in the soil instead of once constintly. when switching out plants you have different nutrients being absorbed at different speeds and different roots growing differently therfore the spoil and water flow have to adapt and carry fresh nutrients to carry the constant changes that were going on in the soil.