25.    Ideally, the ingredients of a good marketing mix should:

    a)    be determined by which ingredients cost the least.
  That would be oversimplified and probably ineffective.
 
    b)    not include much advertising because it's expensive.
I can name you a large, very large number of companies which wouldn't do any advertising.

    c)    flow logically from all the relevant dimensions of a target market.
True, this is the only logical answer.

    d)    match the ingredients typically used by key competitors.
This is not as wrong as it may appear, but if you look at the wording of the question, «Ideally» you would not want to do what your competitors are doing.

    e)    all of the above are true.
Obviously not.