You want to design a form validation mechanism. Using string methods, which of the following are the steps involved ?
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Check for the presence of certain characters
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Check the position of substrings
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Test the length of data
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Check the variable type of the strings
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Either ABC
Form validation using string methods typically involves checking character presence (indexOf/includes), substring positions (indexOf/search), and testing data length (length property). All three techniques are commonly used together for robust validation.
Designing a string-based form-validation routine typically combines several string operations: (A) checking for the presence of certain characters (e.g., '@' in an email), (B) checking the position of substrings, and (C) testing the length of the data. All three are legitimate string-method steps, so the intended answer is the composite 'A, B and C'. Option D (checking the variable type of the strings) is a type-check, not a string-method validation step, so it is excluded. The option 'Either ABC' is awkwardly worded but is clearly meant as the 'all of A, B, and C' choice, which is the correct grouping of valid string-based validation steps.