A Country Currently Is Using All Its Land to Produce

A country currently is using all its land to produce wheat and grapes.However,the land most suited to growing grapes is being used to produce wheat,and the land most suited to growing wheat is being used to produce grapes.Which of the following statements is true?

A) Production of both wheat and grapes can be increased by shifting tracts of land to their best uses.
B) Production of both wheat and grapes can be increased only if more land becomes available.
C) production of wheat can increase only if production of grapes decreases.
D) Production of grapes can increase only if more labor and machinery become available.
E) Production of neither wheat nor grapes is possible without more land becoming available.