Declining prices for homes and businesses, the underlying

Declining prices for homes and businesses, the underlying assets of the mortgages that banks issued, is going to force a number of financial instutions to declare bankruptcy in the coming years.

a. the underlying assets of the mortgages that banks issued, is
b. which are the underlying assets that banks issue is
c. the morgages that comprises the underlying assets that are issued by banks, is
d. which banks issue as assests to issue mortgages,are
e. the underlying assets of the mortgages that banks issued, are

As per my understanding the Gerund phrase "Declining prices" if Subject should be Singular, then why is the OA choice plural "are" and not "is"?

Example: Delivering Pizzas IS not a glamorous job, but it pays my bills.

Can anyone explain? What is the difference between the Sentence and the example above?

The first clause acts like a modifier . Because it has the present participle "declining"), hence the successive clause should start with the word which is being modified. This leaves us with only A and E. Since "prices" is plural, E wins.

Declining prices for homes and businesses, the underlying assets of the mortgages that banks issued, is going to force a number of financial institutions to declare bankruptcy in the coming years.