Answer:
The correct answer is letter "D": adding more such stock will reduce the portfolios beta coefficient and thus its systematic risk.
Explanation:
The Beta coefficient portraits the volatility of a stock according to the movements of the overall market. It gauges the systematic risk of a portfolio according to what is happening in the stock market. In that sense, by adding stocks randomly without studying the performance of the ticker, it will decrease the reliability of the return strategy chosen for the portfolio, which will reduce immediately the beta coefficient.