Digit-to-symbol substitution (numbers → symbols): 1 → !, 2 → @, 3 → #, 4 → $, 5 → %, 6 → ^, 7 → &, 8 → *, 9 → +. Using this mapping, how is the number 15384 written in code?

Introduction / Context:
Here, each digit 1–9 has a unique symbol. The job is to encode a multi-digit number by simple position-wise substitution. This tests exact recall of the mapping and preservation of order without inserting or omitting symbols.

Given Data / Assumptions:

• Mapping: 1→!, 2→@, 3→#, 4→$, 5→%, 6→^, 7→&, 8→*, 9→+.
• Target numeral: 15384.
• No spaces are required mathematically, but options display spaces for readability; we match their display style.

Concept / Approach:
Apply direct substitution left-to-right, digit by digit, strictly using the provided mapping. No arithmetic is performed.

Step-by-Step Solution:

Verification / Alternative check:
Re-read the mapping to ensure each symbol corresponds to the intended digit and that the sequence order matches 1-5-3-8-4. Everything aligns exactly with option “! % # * $”.

Why Other Options Are Wrong:

• ! $ # ^ &: Maps 5→% incorrectly as $, and 8→* incorrectly as ^; also ends with “&” which is 7, not 4.
• & $ # @ ^: Begins with 7 (“&”) not 1; contains 2 (“@”) and 6 (“^”) which are absent in 15384.
• * $ % ^ &: Starts with 8, not 1; includes 6 and 7 which are not in the target.
• None of these: The correct encoding is present, so this is invalid.

Common Pitfalls:
Copying symbols out of order, confusing similar-looking symbols, or attempting to compress consecutive symbols. Maintain a strict one-to-one, position-wise mapping.

Final Answer:
! % # * $