Which three food grain crops together contribute the maximum share to global food grain production among the combinations given?

Introduction / Context:
This question checks basic knowledge of world agriculture, specifically which major cereals dominate global food grain production. Understanding which crops feed the majority of the world population helps learners appreciate patterns of cultivation, trade, and food security. The focus is on the top three staple cereals by production volume.

Given Data / Assumptions:

• The question asks for three crops that together contribute the maximum to world food grain production.
• Options provide different combinations of cereals including wheat, rice, maize, barley, sorghum, and oats.
• We assume awareness that wheat, rice, and maize are the leading cereals globally.

Concept / Approach:
Global production statistics consistently show that wheat, rice, and maize are the top three cereals by tonnage. Maize sometimes leads in total production because it is also used as animal feed and for industrial purposes. Wheat and rice are central to human diets across many countries. Other cereals like barley, sorghum, and oats are important regionally but do not match the combined contribution of wheat, rice, and maize. The correct approach is to choose the combination that includes these three major crops.

Step-by-Step Solution:
Step 1: Recall the main staple cereals grown worldwide for food and feed. Step 2: Recognise that wheat, rice, and maize occupy the top positions in global cereal production data. Step 3: Look at the combinations in the options and identify the one that includes all three of these crops. Step 4: Note that the combination wheat, rice, maize appears as one of the options. Step 5: Select wheat, rice, maize as the correct answer.

Verification / Alternative check:
Food and Agriculture Organization statistics on cereal production show maize, wheat, and rice as the three largest crops by quantity. This pattern has persisted for many years, though their exact ranking among themselves can vary slightly by year. Reference books for geography and agriculture summarise this information and often directly state that wheat, rice, and maize together account for the majority of global cereal output. Since no other combination in the options captures all three of these crops together, the answer is clearly wheat, rice, maize.

Why Other Options Are Wrong:
Wheat, rice, barley: Barley is smaller in total production compared to maize, so this combination does not represent the three largest contributors.
Rice, maize, sorghum: Sorghum is important in dry regions but its global production is lower than that of wheat.
Wheat, maize, sorghum: Once again, sorghum replaces rice here, which is not accurate for top three global cereals.
Rice, barley, oats: Both barley and oats are produced in much smaller quantities than wheat and maize, making this combination incorrect.

Common Pitfalls:
Some learners may focus on crops familiar in their region rather than on global patterns, causing them to overestimate the importance of barley or sorghum. Another pitfall is to think only in terms of human food and overlook maize because of its large role as animal feed and industrial raw material. To avoid such mistakes, it is important to rely on global production rankings rather than local experience.

Final Answer:
The three crops that together contribute the maximum to global food grain production are wheat, rice, and maize.