The correct answer is: D. sector rotation.
Sector rotation is a strategy that involves shifting the weights of securities in a portfolio to take advantage of areas that are expected to do relatively better than other areas. This can be done by buying securities in sectors that are expected to do well and selling securities in sectors that are expected to do poorly.
Portfolio management is the process of managing a portfolio of assets, such as stocks, bonds, and other investments. This includes decisions about what assets to buy, when to buy them, and when to sell them.
Market timing is the attempt to predict the future direction of the market and buy or sell assets accordingly. This is a very difficult task to do successfully, and most investors are better off not trying to time the market.
Momentum strategy is a strategy that involves buying assets that have been doing well in the past and selling assets that have been doing poorly. This strategy is based on the idea that past performance is a good predictor of future performance. However, momentum strategies can be risky, as past performance is not always indicative of future results.