Which of the following statements best describes the error message "one of the variables needed for gradient computation has been modified by an inplace operation"?
A. It indicates that a variable used in calculating gradients has been altered by a non-inplace operation.
B. This error suggests that a variable required for gradient calculation was modified directly within the computation graph.
C. It signifies that a variable involved in gradient computation was changed by an operation that doesn't directly modify the variable.
D. It implies that a variable used for gradient computation has been updated by an operation that modifies it in place.