Out of the four alternatives, choose the single word that can be used in place of the given description. Action that is likely to make people very angry.

Introduction:
One word substitution questions check whether you know precise vocabulary items that condense longer descriptions into single words. Here you must choose a word that describes an action likely to make people very angry. This is important for reading news, legal reports, and essays where such precise adjectives are frequently used.

Given Data / Assumptions:
- Description: "Action that is likely to make people very angry."
- Options: "Inflationary", "Inflammable", "Commensurable", and "Inflammatory".
- Each word looks somewhat similar in spelling, which makes recognition more challenging.

Concept / Approach:
The correct word here is "inflammatory". In everyday English, "inflammatory" language or action tends to arouse strong feelings, especially anger, hatred, or violence. The other options have very different meanings: "inflationary" relates to economic inflation, "inflammable" to catching fire easily, and "commensurable" to comparability in size or measurement. The approach is to recall the specific context in which each word is normally used and match that context with the description.

Step-by-Step Solution:
Step 1: Consider "inflammatory". You may have seen phrases like "inflammatory speech" or "inflammatory remarks" in newspapers, which refer to comments that provoke anger or unrest.Step 2: Check whether this fits the description "Action that is likely to make people very angry." Yes, it matches exactly.Step 3: Examine "inflationary". This is used mainly in economics, as in "inflationary policies" that increase prices, and is not about anger directly.Step 4: Examine "inflammable". This word describes substances that catch fire easily, like "inflammable gas", and relates to physical burning, not emotional anger.Step 5: Examine "commensurable". This is a mathematical or technical word for things that can be measured by the same standard, completely unrelated to people's anger. Therefore, "inflammatory" is the correct choice.

Verification / Alternative check:
You can verify by checking typical collocations. Dictionaries show phrases such as "inflammatory article", "inflammatory action", or "inflammatory slogan", which all mean something likely to provoke anger or hostility. In contrast, "inflationary" appears with terms like "pressure", "spiral", or "economy"; "inflammable" with "material" or "liquid"; and "commensurable" with "magnitudes" or "values". This context based check confirms your choice.

Why Other Options Are Wrong:
Option A, "Inflationary", is wrong because it concerns rising prices and the economic phenomenon of inflation. Option B, "Inflammable", means easily set on fire and is a physical property of substances, not a description of emotional reactions. Option C, "Commensurable", is a technical term from mathematics and measurement. None of these words refer to actions that stir up anger. Only option D, "Inflammatory", directly describes such actions or statements.

Common Pitfalls:
Since "inflammable" and "inflammatory" share the root "flame", candidates sometimes confuse them. However, "inflammable" keeps the literal fire related meaning, while "inflammatory" has developed a metaphorical meaning about emotional "fires" such as anger and hatred. Another pitfall is to choose a word based solely on familiarity rather than matching the exact definition. Always read the description carefully and test each option in a natural phrase or sentence.

Final Answer:
The correct one word substitute is Inflammatory.