When two vectors A and B are at an angle 0 degrees (or any multiple of 0 degrees), it means they are parallel to each other. In this case, the magnitude of the vector sum A + B is equal to the magnitude of the vector AMB.

Option 1 states that the magnitude of the vector AMB is equal to the magnitude of the vector sum A + B. This is correct because when two vectors are parallel, their magnitudes add up.

Option 2 states that the sum of the magnitudes of A and B is greater than the magnitude of the vector sum A + B. This is not true because the vector sum will have a magnitude equal to the sum of the magnitudes when the angle between the vectors is 0 degrees.

Option 3 states that the sum of the magnitudes of A and B is less than the magnitude of the vector sum A + B. This is not true for the same reason as option 2.

Option 4 states that the sum of the magnitudes of A and B is equal to the magnitude of the vector difference A - B. This is not relevant to this scenario involving parallel vectors.

Hence, the correct answer is option 1 - |AMB| = |A + B|.