When using === for comparison, which of the following does it not allow?

Using the strict comparison operator === in PHP checks both the value and the type of the operands being compared. When === is used, it requires that the two variables being compared not only have the same value but also be of the same data type.

For example, if you compare an integer with a string representation of that integer, the comparison will yield false, as their types differ (integer vs. string). This strict type comparison is what distinguishes === from the loose equality operator ==, which converts values to a common type before comparing them.

In the context of the other options:

• Arrays with the same values can be compared using ===, as two arrays are considered identical only if they have the same keys and values in the same order.
• Identical strings will also compare as true since they have both the same value and type (string).
• Numerical equality, when the types are integers or floats, would also yield true with ===, provided both numbers are of the same type.

Thus, the correct understanding of how === operates leads to recognizing that it does not allow comparisons between different value types, which is why this answer is indeed accurate.