The Rationale Behind Why the Glass-Steagall Act Mandated the Ban

The rationale behind why the Glass-Steagall Act mandated the ban on commercial banks from dealing in securities markets and selling insurance was that such activities:

A) encouraged the banks to engage in fraudulent activities.
B) exhausted the business assets of investment banks and insurance companies.
C) reduced the banks' funds to create loans for their customers.
D) exposed banks and their depositors to higher levels of risk.