Final answer:
Preformatted screens control the entry of data by defining the acceptable format for each data field, ensuring data consistency and validity.
Step-by-step explanation:
The control plan that controls the entry of data by defining the acceptable format of each data field is C) preformatted screens. This method involves setting up the input fields in a way that they only accept data in a specific format, size, or type. For instance, a date field may be preformatted to only accept entries in the format 'MM/DD/YYYY', which prevents users from entering data that could cause errors or inconsistencies. Preformatted screens are a common feature in software applications and web forms, ensuring that the data collected is clean and valid for processing.