The most valid response is:
Yes, because the trees in the sample are chosen randomly. The sample size also appears to be large enough to avoid bias.
The farmer’s method of selecting a random sample of trees is an appropriate statistical practice, and a sample size of 700 from a population of 12,000 is considered large enough to provide a good estimate of the entire population's sweetness. However, it's important to note that while the sample can provide a useful inference, the actual sweetness of all apples from all trees may still vary. Nonetheless, the reasoning given in this response is the best choice among the options provided.