Decode the uppercase string using a Caesar shift of −6 (i.e., shift every letter 6 positions backward), then output the result in lowercase. Given: VPRFKM

Introduction / Context:
A negative Caesar shift moves letters backward. With −6, we map e.g., V→P, W→Q, …, F→Z. After substitution, convert to lowercase.

Given Data / Assumptions:

• Cipher: Caesar −6.
• Input: VPRFKM.
• Output: lowercase string.

Concept / Approach:
Apply −6 to each character modulo 26, preserving order.

Step-by-Step Solution:

Verification / Alternative check:
Re-encode “ocdkzq” with +6; it returns “vprfkm”.

Why Other Options Are Wrong:

• lzcndo, vithaw, cxtndo: These correspond to different shifts and do not invert to VPRFKM under +6.

Common Pitfalls:
Mixing up letter-to-index mapping (A=0 or A=1). Stick to one convention to avoid off-by-one errors.

Final Answer:
ocdkzq