Which step in program development involves carefully reading the problem description until you understand completely what is required?

Programming is an Art. People believes that programmers might be perfectionists in mathematics, where as it can be defined as the development of a solution to an already identified query, and setting up of a related series of instructions. There are 7 main steps to develop a program but the one asked in the question is "Defining the problem".
This step is about carefully reading and proofreading the query until you understand completely what is required. Further, the problem should be divided into 3 separate components:- Input- Output- processing of step to produce output which is required.

6, 4, 5, 1 are true. the others are false.