If a. the resultant force and the component force satisfy the parallelogram law, the resultant force of 10 N must be within the range of the resultant force of the two components, but the resultant force of the two forces in item A is 0≤ F ≤6 N, so the force of 10 N cannot be decomposed into 3 N, 3 N. A, but B, C and D are all possible.