all data processed by a computer must be in

The correct answer would be Binary Form.

Explanation:

All data processed by a computer must be in Binary form. Computers do not understand the raw language used by people or other devices. Rather computers use the machine understandable language which is called the Binary language. Binary language is the language consists of zero and one, 0 & 1. Different combination of 0 & 1 makes the sense of the language which the computers understand. Data which is coming to the computer through the input devices are converted to the binary form in order to be understood and then processed by the computer.