If investors believe a public company's senios executives know substantial inside information, then the management's decision to issue additional shares signals ______ of the company's stock, and the management decision to repurchase (or buy back) existing shares signals ______ of the company's stock.

a) undervaluation, undervaluation

b) undervaluation, overvaluation

c) overvaluation, undervaluation

d) overvaluation, overvaluation