If You Heard Overheard a Farmer Discussing His Planting Plans

If you heard overheard a farmer discussing his planting plans for the upcoming season and he said "The price of corn has gone way up. I know I'll have to put some money into fertilizer on the field where I was going to plant soybeans, but it will be worth it this year." This would be consistent with which justification for an upward sloping supply curve

A) increasing marginal cost.
B) the need for higher prices in one good to motivate a shift in production from another.
C) the real-balance effect.
D) diminishing marginal utility.