Under the Five Forces Model,a Risk to a Firm with a Differentiation

Under the five forces model,a risk to a firm with a differentiation strategy is:

A) When the focus of competition switches to price rather than features and new acceptable levels of quality have emerged due to innovation.
B) When the focus of competition switches to price rather than features and the substitute products are considered below acceptable levels of quality.
C) When the focus of competition switches to features rather than price, the substitute products are considered below acceptable levels of quality.
D) When the focus of competition switches to features rather than price and new acceptable levels of quality have emerged due to innovation.