Final answer:
To calculate the determinant using cofactor expansion, a matrix calculator would be most helpful.
Step-by-step explanation:
When calculating the determinant using cofactor expansion, the most helpful calculator would be a Matrix calculator (option C). Matrix calculators are specifically designed to perform calculations involving matrices, which includes finding determinants. They can handle larger matrices and efficiently calculate the determinants using cofactor expansion. Graphing calculators (option A) and scientific calculators (option B) may have some matrix capabilities, but they are typically limited in terms of matrix size and functionality.