What is the primary reason that system risk exists? a$.$ Financial institutions borrow using long$-$term debt securities but lend their funds for short$-$term periods, b$.$ Financial institutions invest in similar securities and therefore are similarly exposed to large declines in prices of those securities$,$ c$.$ Financial institutions invest heavily in Treasury securities and therefore are exposed to the possibility that the government will default on its debts, or d$.$ There is no government regulation of financial markets