Which choice is the most appropriate first complementary food to prioritize iron intake for a 6-month-old starting solids?

Apple puree and diluted fruit juice because the natural sugars will increase appetite and improve iron absorption

Pureed beef or iron-fortified infant cereal, because they supply bioavailable iron to replenish stores typically depleted by six months

Whole cow's milk offered in a bottle to introduce calcium and indirectly increase iron stores

Raw spinach blended into a smoothie because its green color indicates high iron, making it the best first choice