IDIOMS — Choose the option that best expresses the meaning of the underlined expression in context. Sentence: 'Though he has a lot of money, yet all his plans are built upon sand.'

Introduction / Context:
The idiomatic clause “built upon sand” is a vivid metaphor drawn from construction. It suggests that a plan, promise, or system rests on an unstable base and will likely collapse under stress. The sentence contrasts financial wealth with fragile planning to test whether you can decode figurative meaning rather than read literally.

Given Data / Assumptions:

• The subject has “a lot of money.”
• Despite wealth, “all his plans are built upon sand.”
• We are asked to select the closest paraphrase of the idiom in standard English.
• The focus is the stability of plans, not their cost or novelty.

Concept / Approach:
In English, “to build on sand” means to rely on weak assumptions, dubious data, or unreliable support. The sense is architectural: solid structures require firm foundations; sand shifts. Therefore, the best rendering emphasizes insecurity and likely failure, not merely cheapness, inexperience, or youthfulness of ideas.

Step-by-Step Solution:
1) Identify the idiom: “built upon sand.”2) Map the metaphor to planning: plans will not stand pressure if the base is unstable.3) Compare choices with the core meaning of instability.4) Select the option that foregrounds insecure foundations.

Verification / Alternative check:
Paraphrase the sentence: “Though he is wealthy, his plans rest on insecure foundations.” The contrast now reads cleanly and logically, which verifies the choice.

Why Other Options Are Wrong:
B) “based on inexperience” shifts the cause to personal skill rather than structural instability.C) “resting on cheap material” interprets the metaphor literally and misses the figurative point.D) “resting on immature ideas” focuses on idea maturity, not foundational insecurity.

Common Pitfalls:
Learners often interpret such idioms literally (e.g., sand as cheap material). Always check if the clause functions as a fixed figurative expression about stability.

Final Answer:
established on insecure foundations