Which of the following would reduce a firm's WACC before tax?

a.

A pharmaceutical research company develops a 100% effective COVID vaccine, which reduces its systematic risk in the market.

b.

A firm invests in an average-risk project using debt, rather than equity financing.

c.

A supermarket chain decides to establish hardware stores which increases its sensitivity to market fluctuations.

d.

A firm issues shares and uses the proceeds to pay off a bank loan.

e.

A firm issues bonds and uses the proceeds to repurchase stock.