Which of the following would you classify as a case of cultural evolution?

Which of the following would you classify as a case of cultural evolution?
 
  a. The males of brood parasitic birds (e.g., cuckoos) use the calls of their father after they have been raised in the nest of a host.
  b. The specific arrangement of keys on a keyboard of a computer that has been steadily gaining market share during the past decade.
  c. A parent offspring regression in catbirds yields a linear slope of 0.9 when the ability to acquire new calls is plotted.
  d. The cases made by the larvae of the same caddisfly species differ between different sections of the stream depending on the availability of construction materials.