When asked about the number of ways to combine, distribute, mix or divide objects, in this case answers, we use a counting method to calculate the number of possibilities.
In this case we have the possibility to respond from <em>AAAA</em>, <em>AAAB</em>, <em>AAAC</em>, <em>AAAD</em>, <em>AABA</em>, <em>AABB</em>, ..., <em>CADB</em>, to <em>DDDD</em>; to calculate how many are we must take into account that for each possible answer of a question we have four options of the other, so, for the 4 options of question 1 we have 4 options of question 2 and for each of these, four of the question 3 and so.
Then, the answer will be 4*4*4*4 = 256 different ways for answer the questions