The correct sentence is:
B - Mr. and Mrs. Johnson moved next door to us.
This sentence uses the simple past tense correctly for the plural subject "Mr. and Mrs. Johnson."
A-Mr. and Mrs. Johnson moves next door to us.
B-Mr. and Mrs. Johnson moved next door to us.
C-Mr. and Mrs. Johnson is moving next door to us.
D-Mr. and Mrs. Johnson has moved next door to us.
The correct sentence is:
B - Mr. and Mrs. Johnson moved next door to us.
This sentence uses the simple past tense correctly for the plural subject "Mr. and Mrs. Johnson."