I would like the answer to the following question (with workings and explanations please):

Suppose there are two mortgage bankers. Banker 1 has two $800,000 mortgages to sell. The borrowers live on opposite sides of the country and face an independent probability of default of 6%, with the banker able to salvage 35% of the mortgage value in case of default. Banker 2 also has two $800,000 mortgages to sell, but Banker 2's borrowers live on the same street, have the same job security and income. Put dierently, the fates and thus solvency of Banker 2's borrowers move in lock step. They have a probability of defaulting of 4%, with the banker able to salvage 35% of the mortgage value in case of default. Both Bankers plan to sell their respective mortgages as a bundle in a mortgage-backed security (MBS) (i.e., as a portfolio). Which of the following is correct?

Is the answer:

a) Banker 2's MBS has a higher expected return and more risk

b) Banker 1's MBS has a lower expected return and more risk.

c) Banker 1's MBS has a higher expected return and less risk

d) Banker 2's MBS has a low expected return and more risk.