In What Way Do the Last Two Phases in the Development

In what way do the last two phases in the development of causal schemes and experimentation with new means and insight differ?

A) In the last phase, there is no experimentation, just direct solution of a problem.
B) In the last phase, there is no planning.
C) In the last phase, babies use novel means to achieve novel goals.
D) In the last phase, experimentation is carried out mentally rather than directly.