1. Let's analyze the accepted characters in the context given. 2. Accepted characters include: - Numbers (0-9). - Decimal point markers represented by a period (e.g., 3.14). - Sign indicators like "-" for negative numbers. - Spaces for grouping digits (e.g., "5 000" for five thousand). - "E" or "e" used strictly for scientific notation, where a period must be the decimal point marker (e.g., 1.23E4). 3. For complex numbers, the format must be explicitly {a+bi} where both a and b are numerical values. - Example: {1+1i} is valid. - {1+i} is invalid because b is not explicitly stated. - {0+9i} is valid. - {9i} is invalid because a is missing. 4. This ensures clarity and unambiguity in notation for parsing or computations. Final answer: The accepted characters are numbers, . (decimal point), - (sign), spaces, E or e for scientific notation with period decimal, and complex numbers strictly formatted as {a+bi} with explicit a and b values.