Explanation

Green vegetables are typically rich in lysine but limiting in methionine. However, the question asks for the limiting amino acid in green vegetables specifically. While grains are limiting in lysine and legumes in methionine, green vegetables generally have a good balance but are often cited as being relatively low in sulfur-containing amino acids like methionine compared to animal proteins, or sometimes tryptophan depending on the specific vegetable. Wait, let's double check standard nutrition MCQs. Common knowledge: Cereals are limiting in lysine. Legumes are limiting in methionine. Green vegetables? Actually, many sources state that green leafy vegetables are good sources of lysine and are not typically considered 'limiting' in the same way grains/legumes are, but if forced to choose among options for plant foods generally, methionine is often the limiting one for plant-based diets overall. However, specific MCQs on this topic often point to Methionine as the limiting amino acid for many plant sources including some vegetables, or sometimes Tryptophan for maize. Let's look at standard PrepBeePakistan context. Usually, for 'green vegetables' specifically, they are considered complete or near-complete but if a limiting one must be picked, Methionine is the most common answer for plant proteins in general MCQs. Wait, some sources say green vegetables are rich in Lysine and limiting in Methionine? Actually, legumes are rich in lysine/limiting methionine. Green vegetables are often grouped with legumes in terms of lysine content. So Methionine is the likely intended answer for plant foods. But let's check if there's a trick. Some sources say green vegetables are limiting in Tryptophan? No, that's maize. I will stick with Methionine as it is the standard limiting amino acid for most plant proteins except legumes/grains where lysine is limiting. Wait, legumes limit methionine. Green vegetables are like legumes in lysine content. So they limit methionine. The current answer A is likely correct. I will confirm A.