What is the number of credits required for fully insured status for social security disabilitiy benefits?

There are three factors that can affect the shape of the treasury yield curve (r* t , ip t , and mrp t ) and five factors that can affect the shape of the corporate yield curve (r* t , ip t , mrp t , drp t , and lp t ). the yield curve reflects the aggregation of the impacts from these factors. suppose the real risk-free rate and inflation rate are expected to remain at their current levels throughout the foreseeable future. consider all factors that affect the yield curve. then identify which of the following shapes that the us treasury yield curve can take. check all that apply.a. downward-sloping yield curveb. upward-sloping yield curvec. inverted yield curve