The correct answer is B) Double displacement.
This is because the Barium (Ba), which has a positive charge, got rearranged to bond with the carbonate (CO3), which has a negative charge. Also, the potassium (K), which has a positive charge, bonded with the chlorine (Cl), which has a negative charge.
It helps to remember that when there is a double replacement there are 4 elements/molecules in the reactants and 4 in the products that get rearranged.
Hope this helps!
