Final answer:
The Linear Algebra with Applications 5th edition by Otto Bretscher is not available online.
Step-by-step explanation:
The subject of this question is Mathematics because it is asking about the availability of a specific linear algebra textbook.
The answer to this question is B) Not available. The information provided does not mention the availability of the Linear Algebra with Applications 5th edition by Otto Bretscher online. Therefore, it can be inferred that it is not available.