It becomes particularly urgent for a company to consider diversification when there are

The company could consider diversifying when sales are beginning to slow and there is a way to leverage some of the business's core competencies in other areas that would be more competitive. In addition, this could allow the business to not worry about being "all-in" in a certain area, where that area's success or failure could lead to the entire business thriving or failing. By diversifying itself, the business can also lower production and sales costs or increase overall sales.

Any choices

Answerwinchell would use the residual method($120-$100)=$20;