What is the correct format for a Canadian Postal Code in Regular Expression?

The correct format for a Canadian Postal Code in a Regular Expression adheres to the structure of alternating letters and numbers with a specific arrangement. In a Canadian Postal Code, the format consists of a letter followed by a number, followed by another letter, then a space, and finally a number followed by a letter and ending with another number (A1A 1A1).

The option identified accurately represents this format, beginning with a letter, followed by a digit, another letter, a space, then a digit, a letter, and concluding with a digit. This sequence is crucial, as it reflects the mandated pattern for Canadian Postal Codes, distinguishing it from other formats such as ZIP Codes from the United States.

The other choices either do not follow the proper sequence or use incorrect characters, making them unsuitable representations for a valid Canadian Postal Code. For instance, combinations that start with numbers or lack the necessary spacing and letter-digit alternation as mandated by the Canadian postal system would not be valid representations.