Classification – Odd one out (initial letter grouping): Choose the word unlike the others: Head, Heed, Sledge, Heap.

Introduction / Context:
Some verbal classification items hinge on spelling/phonetic clusters. Three of these words start with the same two-letter sequence “He…”. One begins with an entirely different initial consonant cluster, producing a clear odd one out.

Given Data / Assumptions:

• Head, Heed, Heap → begin with “He”.
• Sledge → begins with “Sl”.

Concept / Approach:
Use a simple orthographic test (first two letters). If three share “He-” and one does not, the nonconforming item is the outlier.

Step-by-Step Solution:
Check prefixes: Head → He; Heed → He; Heap → He.Sledge → Sl → distinct initial cluster.

Verification / Alternative check:
Other properties (vowel length, syllable count) are less decisive and do not provide a 3-to-1 split as cleanly as the initial cluster does.

Why Other Options Are Wrong:

• Head, Heed, and Heap share the “He-” start and thus belong together.

Common Pitfalls:
Overfitting to meanings; orthographic/phonetic patterns are a valid and common basis for such items.

Final Answer:
Sledge