In your own words,

a) Describe a mortgage backed security and a collaterlized debt obligation.

b) What is contagion? How does it work?

c) How would a crisis of any type in one country lead to a financial crisis in another?

d) What can MNEs do to protect themselves against situations like the 2007-2009 financial crisis?

(Do not give me short one sentence answers. Aim for circa 500 words total.)