Tax shields Compute the present value of interest tax shields generated by these three debt issues. Consider corporate taxes only. The marginal tax rate is $T_c=\mathrm{.}35.$

a$.$ A $$1,000,$ one$-$year loan at $8\%.$

b$.$ A five$-$year loan of $$1,000$ at $8\%.$ Assume no principal is repaid until maturity.

c$.$ A $$1,000$ perpetuity at $7\%$