Which format is used for automatic numeric to character conversion?

The format used for automatic numeric to character conversion is best.12. This is because the best. format is designed to provide a default display for numeric values that optimally fits the data, using up to the specified number of characters to represent the numeric value accurately.

In this case, best.12 allows for sufficient space to represent larger numeric values without losing precision. The numeric values will be represented in a character format, making it easier for character operations to be carried out on them after the conversion.

The other formats listed are either not specifically designed for this purpose or do not provide enough space for larger numbers, which can result in truncated or misrepresented values.