When Writing Items for a New Test,what 'Rule of Thumb

When writing items for a new test,what 'rule of thumb' has been verified repeatedly over decades of test development?

A) Draft the exact number of items you expect to need on the test.
B) Draft at least twice as many items as you expect to need on the test.
C) Draft at least three times as many items as you expect to need on the test.
D) Draft at least four times as many items as you expect to need on the test.