When do people tend to pursue significant kinds of change?

When do people tend to pursue significant kinds of change?
 
  a. When modifications don't work, or when we experience a level of distress that
  significantly interferes with our ability to function
  b. When we can't think of anything to do, or when we experience a level of
  distress that significantly interferes with our ability to function
  c. When our social supports can't help, or when we experience a level of distress
  that significantly interferes with our ability to function
  d. When modifications don't work, or when we start feeling distressed