A$.$ You would receive $$15\mathrm{.}63$ because markets are efficient and would incorporate the information about the new growth rate immediately.

B$.$ You would receive $$35\mathrm{.}71$ because when you bought the stock, the dividend growth rate was still $7\mathrm{.}0\%.$

C$.$ You would receive $$35\mathrm{.}71$ if you act very quickly because it takes a day or two for markets to incorporate the information about the new growth rate

D$.$ You would receive a price between $$15\mathrm{.}63$ and $$35\mathrm{.}71$ because you should get a blend of the old and new growth rate of dividends.