Final answer:
The best estimate for the capacity of the bottle when filled to the FULL mark is 500 mL, as it is a reasonable approximation compared to a similar-sized soda bottle, which holds 1 liter.
Step-by-step explanation:
The question asks for the best estimate of how much liquid a bottle can hold when filled to the FULL mark, given that it contains 200 mL of liquid plant food. Considering that a soda bottle, which has a similar size to many household liquid containers, holds about 1 liter (or 1,000 mL), we can infer that the correct answer would likely be closest to a 1 liter capacity. Therefore, the best estimate for how much the bottle can hold when filled to the FULL mark is option B: 500 mL, which is half a liter and a more reasonable estimate given the information provided than 1,000 mL. It's important to note that the bottle currently has 200 mL, so its full capacity should definitely be more than that amount.