The taxable gain is approximately $14,100.50. The closest option is "O $14,100."
To calculate the taxable gain, we need to determine the cost basis of Addie's shares, which includes both the original purchase price and the additional shares purchased with the dividend payments.
Original Purchase:
Original Shares Cost=Number of Original Shares×Original Purchase Price per Share

Dividend Reinvestment:
Addie received $1,900 in dividend payments, which purchased an additional 145 shares.
Cost of Additional Shares=Number of Additional Shares×Average Cost per Additional Share
Average Cost per Additional Share= Total Dividend Payments/ Number of Additional Shares

Total Cost Basis:
Total Cost Basis=Original Shares Cost+Cost of Additional Shares

Taxable Gain:
Taxable Gain=Selling Price−Total Cost Basis

Therefore, the taxable gain is approximately $14,100.50. The closest option is "O $14,100."