Step 1: Understand what the question is asking.
The question asks which food listed provides the greatest amount of protein compared to the others.
Step 2: Note on option A.
The text for option A is missing in the source material for this question, so it cannot be evaluated here. The comparison below covers the three legible options, gram, peas, and soybean.
Step 3: Compare the protein content of gram, peas, and soybean.
Gram and peas are both pulses, and pulses generally carry protein in the range of 18 to 25 percent by weight. Soybean, however, stands out among common food crops with a protein content of about 40 percent or more, nearly double that of most other pulses. This makes soybean the richest ordinary source of protein among plant foods.
Step 4: Final answer.
Since soybean carries a far higher protein share than gram or peas, soybean is the largest source of protein among the given options.
\[ \boxed{\text{Soybean}} \]