$51.$ A downward sloping yield curve indicates that future short$-$term rates are expected to a$.$fall; rise.b$.$ fall; fall.C$.$rise; rise.d$.$ rise; fall$\mathrm{.}52.$ According to the expectations theory of the term structure of interest rates, a$.$investors prefer holding short$-$term securities$.$b$.$ the shape of the yield curve is determined by investors' expectations of futureC.institutional investors' maturity preferences determine the shape of the yield curve.d$.$ investors always expect short$-$term interest rates to increase.e$..$both a and b$53.$ The major determinant of the bond ratings assigned by Moody's, S