Final answer:
Without additional context or a specific reference grid or pattern, it is not possible to determine which letter corresponds to the position (2, -7).
Step-by-step explanation:
To determine which letter is at position (2, -7), we likely need more context such as a particular pattern, grid, or cipher that relates to this coordinate. However, without such context provided in the question, it is not possible to give a definitive answer. In typical Cartesian coordinates, positions are given as (x, y) where x is the horizontal position and y is the vertical position. But, without a specific pattern or reference grid, we cannot correlate these positions to letters.
If this question refers to a grid where letters are arranged and each letter has been assigned a coordinate, then the letter corresponding to the position (2, -7) would depend on the specific arrangement of that grid. Some cipher systems or puzzles can also use coordinate systems to encrypt letters, but again, without more information, we cannot give a correct answer to which letter corresponds to (2, -7). If the student can provide additional information or clarify the context of the question, a more accurate response might be formulated.