Filters on formula fields that are non-deterministic can’t be indexed and result in additional joins. Common formula field practices include transforming a numeric value in a related object into a text string or using a complex transformation involving multiple related objects. In both cases, if you filter on this formula field, the Force.com query optimizer must join the related objects.

https://developer.salesforce.com/blogs/engineering/2013/07/maximizing-the-performance-of-force-com-soql-reports-and-list-views

Based on official Salesforce documentation answers: B C D

B,D,E
The answer is correct.
Large data loads and deletions can affect query performance, but it does not affect query selectivity.

B,C,D

Base on this document. We can figure out the correct answer is B C D
https://developer.salesforce.com/blogs/engineering/2013/07/maximizing-the-performance-of-force-com-soql-reports-and-list-views.html

https://developer.salesforce.com/blogs/engineering/2013/07/maximizing-the-performance-of-force-com-soql-reports-and-list-views.html
"Large data loads and deletions can affect query performance. "

should be ADE

ABD is the correct answer.

The correct answer is B C D

A, B, E