In a certain code language, "851" means "good sweet fruit", "783" means "good red rose" and "341" means "rose and fruit". In this language, which digit stands for the word "sweet"?

Introduction / Context:
This is a digit-based coding question where each word is represented by a numeric digit. Several short coded sentences with overlapping words are given. By comparing the sentences, we can deduce which digit corresponds to which word. The task here is to find the digit representing "sweet". This problem tests logical deduction and systematic use of intersections between small sets of digits and words.

Given Data / Assumptions:

• "851" = "good sweet fruit".
• "783" = "good red rose".
• "341" = "rose and fruit".
• Each word is uniquely represented by one digit.
• The mapping is consistent across all the sentences.

Concept / Approach:
We compare pairs of code sentences and their meanings. Common words correspond to common digits. By starting with obvious overlaps such as "good" and "rose", we can label the digits for those words, then deduce "fruit". The remaining digit in the first sentence will then stand for "sweet". This is a direct application of logical set intersection and elimination.

Step-by-Step Solution:
Step 1: Compare "851" ("good sweet fruit") with "783" ("good red rose"). Step 2: Common English word is "good". Step 3: Common digit in 851 and 783 is 8. So 8 → "good". Step 4: Compare "783" ("good red rose") with "341" ("rose and fruit"). Step 5: Common English word is "rose". Step 6: Common digit in 783 and 341 is 3. So 3 → "rose". Step 7: Compare "851" ("good sweet fruit") with "341" ("rose and fruit"). Step 8: Common English word is "fruit". Step 9: Common digit in 851 and 341 is 1. So 1 → "fruit". Step 10: Now in "851" we have digits 8, 5, 1 corresponding to "good", "sweet", "fruit". We already know 8 → "good" and 1 → "fruit". Step 11: The remaining digit in 851 is 5, so 5 must represent "sweet".

Verification / Alternative check:
You can construct the full mapping: 8 → good, 3 → rose, 1 → fruit, 5 → sweet, and remaining digits correspond to "red" and "and". Rebuilding each sentence using this mapping results in the correct English phrases, confirming consistency. Because "sweet" appears only in the first sentence, and after accounting for "good" and "fruit" we are left only with digit 5, the conclusion is secure.

Why Other Options Are Wrong:
Option A (8) is already mapped to "good". Option C (1) is mapped to "fruit". Option D (3) is mapped to "rose". Option E (7) appears only in "783" and must therefore correspond to "red", not to "sweet". Only Option B, digit 5, remains and correctly matches the word "sweet" after all other mappings are fixed.

Common Pitfalls:
A typical mistake is to try to guess the mapping without fully using all the sentences, which can result in multiple inconsistent possibilities. Another pitfall is forgetting that the mapping is one-to-one, so a digit already assigned to one word cannot represent another. To avoid confusion, always mark mappings as you derive them and cross-check with all given sentences.

Final Answer:
Hence, in the given digit code, the word "sweet" is represented by the digit 5.