Portfolio A had an unsuccessful stock selection. This is indicated by the negative alpha coefficient of -1.0. The alpha coefficient is a measure of the performance of an investment against a market index or other benchmark which the investment is expected to follow. A negative alpha indicates that the investment has underperformed compared to the benchmark. In this case, the negative alpha for Portfolio A suggests that the stock selection for this portfolio was unsuccessful, as it underperformed compared to its benchmark.

Choice B is incorrect. The statement that both portfolios have no evidence of an attempted timing is not accurate. Portfolio A has a timing coefficient of 0.05, which indicates some level of attempted timing, even though it may not be significantly successful.

Choice C is incorrect. There's no evidence to suggest that Portfolio B has successful timing as its timing coefficient is 0. A positive and significant timing coefficient would indicate successful market-timing ability.

Choice D is incorrect. The statement that portfolio B had an unsuccessful stock selection isn't correct because the alpha coefficient for portfolio B was positive (1.75), indicating a successful stock selection strategy.