In the following question, choose the word that is opposite in meaning to the adjective Profound, which describes something very deep, intense, or intellectually serious.

Introduction / Context:
This antonym question focuses on the word Profound, a common term in academic writing, philosophy, and literary criticism. Profound describes ideas, feelings, or changes that are very deep, intense, or significant. To find the correct answer, you must choose the option that clearly expresses the opposite idea, namely something shallow or lacking depth.

Given Data / Assumptions:

• Target word: Profound.
• Options: Mysterious, Difficult, Superfluous, Superficial.
• You must select the option whose meaning is opposite to Profound in sense of depth and seriousness.
• The context is emotional depth or intellectual depth, not just difficulty or quantity.

Concept / Approach:
Profound often describes thoughts, questions, discoveries, or emotions that reach far below the surface. The opposite of this depth is something that only touches the surface, lacks seriousness, or is shallow. Superficial captures this meaning exactly. It refers to something that is only on the surface, not thorough, and lacking real depth. Mysterious and Difficult may relate to complexity, but not necessarily to depth or its absence. Superfluous means unnecessary or extra, which is not the central opposite of Profound.

Step-by-Step Solution:
Step 1: Recall that Profound means very deep, intense, or far reaching in thought and feeling. Step 2: Consider Mysterious. This means difficult to understand or explain, but something can be mysterious without being shallow or deep in the specific sense of Profound. Step 3: Consider Difficult. This simply means hard to do or understand and does not directly address depth or superficiality. Step 4: Consider Superfluous. This means more than is needed, unnecessary, or excessive. It is related to quantity but not directly to depth. Step 5: Consider Superficial. This means existing only on the surface, lacking depth, or concerned only with outward appearance. Step 6: Conclude that Superficial is the clear opposite of Profound.

Verification / Alternative check:
Think of paired sentences such as The book offers a profound analysis of human nature versus The book offers a superficial analysis of human nature. These two descriptions express opposite evaluations of depth and seriousness. Replacing Profound with Superfluous or Mysterious does not create such a clean opposition. Similarly, calling a change profound suggests that it is far reaching, while calling it superficial suggests that it is only on the surface. This confirms that Superficial is the correct antonym here.

Why Other Options Are Wrong:
Mysterious: Focuses on being hard to explain, which can coexist with depth rather than oppose it.
Difficult: Refers to the level of effort required, not to depth versus shallowness.
Superfluous: Means unnecessary or excessive, not shallow. A profound argument might still contain some superfluous details.

Common Pitfalls:
Candidates sometimes confuse Difficult with Profound because both can appear in discussions of complex ideas. However, an idea can be difficult to understand without being deep or meaningful, and some profound truths are expressed very simply. The key is to focus on the idea of depth. When you see Profound, think of something that goes deep, and when you see Superficial, think of something that stays on the surface. Keeping such mental images can help you remember antonym pairs more reliably.

Final Answer:
The antonym of Profound is Superficial, so option d is correct.