Which statement best describes the results of this study?
a. Trade-offs between seed size and seed number existed in both the control and the fertilizer groups, and these trade-offs were of roughly equal magnitude.
b. Trade-offs between seed size and seed number existed in both the control and the fertilizer groups, but these trade-offs were much larger in the fertilizer group.
c. A trade-off between seed size and seed number existed in the control group but not in the fertilizer group.
d. A trade-off between seed size and seed number existed in the fertilizer group but not in the control group.