A developer creates a method in an Apex class and needs to ensure that errors are handled properly.What would the developer use? (There are three correct answers.)

To which primitive data type is a text area (rich) field automatically assigned?

A develop created these three roll-up summary fields on the custom object. Project_c:

The developer is asked to create a new field that should the ratio between rejected and approved timesheet for a given project.
What are two benefits of choosing a formula held instead of an Apex trigger to fulfill the request? Choose 2 answers

A developer needs to create a custom visualforce button for the opportunity object page layout that will cause a web service to be called and redirect the user to a new page when clicked. Which three attributes need to be defined in the <apx:page> tag of the visualforce page to enable this functionality?