Validate virtual credit card transactions from encoded IDs

You are designing logic for a **virtual credit card** product. ## Part 1: Product reasoning Explain key benefits and drawbacks of virtual credit cards for: - end users, - the issuer (e.g., a bank). ## Part 2: Transaction validation rules A transaction is described by: - `card_number`: a 16-digit string - `transaction_id`: an 8-digit string - `amount`: integer dollars Certain attributes are encoded in the digits: ### Transaction ID (8 digits, positions counted from left starting at 1) - If the **7th** digit is `1` ⇒ transaction is **online**; if `0` ⇒ **offline/in-person**. - If the **6th** digit is `1` ⇒ type is **charge**; if `0` ⇒ type is **authorization**. ### Card number (16 digits, positions counted from left starting at 1) - If the **15th** digit is `1` ⇒ **merchant-bound**; if `0` ⇒ **not merchant-bound**. - If the **14th** digit is `1` ⇒ network is **Master**; if `0` ⇒ **Visa**. - If the **13th** digit is `1` ⇒ **multi-use**; if `0` ⇒ **one-time-use**. ### Validity rules by network A transaction is valid if it satisfies the rules for its network: **Visa**: valid iff - (`merchant_bound` AND `multi_use`) OR - (`online` AND `amount < 100` AND type is NOT `authorization`) **Master**: valid iff - (`amount < 100` AND (online OR offline) AND NOT `merchant_bound`) OR - (`merchant_bound` AND `amount > 100`) ## Tasks 1. Describe an approach (data model + validation flow) to determine whether a transaction is valid. 2. For the following example, determine whether it is valid: - `card_number = "1234567891011111"` - `transaction_id = "50781100"` - `amount = 150` 3. Explain how you would test this logic (unit tests and edge cases).