To solve this question, the user needs to have knowledge of JCL (Job Control Language).
The statement that marks the beginning of a job step; assigns a name to the step; identifies the program or catalogued or in-stream procedure to be executed in the step is EXEC
.
Now, let's go through each option and explain why it is right or wrong:
A. RUN: This option is incorrect. RUN is not a valid JCL statement.
B. START: This option is incorrect. While START is a valid JCL statement, it is not used to begin a job step.
C. EXEC: This option is correct. EXEC is the JCL statement that marks the beginning of a job step, assigns a name to the step, and identifies the program or catalogued or in-stream procedure to be executed in the step.
D. GO: This option is incorrect. GO is not a valid JCL statement.
The Answer is: C