Realize switching function using only 2/4 decoders and logic gates
Use 3 2-to-4 decoders, one with inputs C and D, one with A and B, and one with inputs B and D. Take the output which satisfies
  CD,A′B,BD′
  respectively and then combine them using an OR gate to get the function I needed


This is indeed a correct implementation and is as shown in the diagram above.