What happens if you use automatic variable conversion in SAS?

When automatic variable conversion occurs in SAS, it means that SAS attempts to convert one data type to another, such as from character to numeric, or vice versa, when performing operations involving mixed data types. The correct answer highlights that this conversion may fail due to special characters present in the character values.

For example, if you're trying to convert a character string that contains letters or special symbols to a numeric value, SAS will not successfully convert that string into a number, leading to potential errors or missing values in your dataset. This could cause issues in data analysis or processing as SAS would not interpret these values as numeric, thereby affecting calculations that require numeric data.

In contrast, the other options do not accurately capture the complexities of automatic variable conversion in SAS. The conversion process does not always succeed, and it is not limited strictly to numeric values, as it can also involve converting character data to numeric. Moreover, it does not inherently enhance data processing speed; in fact, the need for conversion may slow down operations, particularly if errors occur.