Final answer:
Option A: Error handler codes in software development are almost never executed, as they are designed to handle unexpected events that occur infrequently during a program's normal operation.
Step-by-step explanation:
The question relates to error handler codes, which are an integral part of programming and software development. Error handler codes are designed to respond when unusual or unexpected events occur that disrupt the normal flow of a program. The correct answer to the question is: a) Almost never executed. Error handler codes are indeed part of a program's defensive programming strategy, meant to address exceptions or errors that are not expected to occur frequently during normal operations. If a program is well-designed and running under normal conditions, such errors will be rare, thus the error handlers will also be triggered infrequently.
Error handler codes are used to handle unusual errors in programming. They are often written as part of a program's exception handling mechanism. The purpose of error handler codes is to provide a way for the program to gracefully handle unexpected situations and prevent the program from crashing or producing incorrect results. These codes are typically executed when an error occurs, making option b) 'Executed very often' the correct answer.