Engineering economy — what does it encompass? (Choose the most complete statement about the scope and purpose of engineering economy.)

Introduction / Context:
Engineering economy provides structured methods to evaluate alternatives over time using cash flows, interest, inflation, taxes, and risk. It informs design, procurement, maintenance, and replacement decisions.

Given Data / Assumptions:

• Alternatives differ in cost, timing, and benefits.
• Decision makers need a consistent basis of comparison.
• Time value of money is relevant.

Concept / Approach:
The discipline blends terminology (e.g., present worth, annual worth, rate of return), mathematics (compounding/discounting), and decision tools (incremental analysis, breakeven, replacement, optimization). Proper application requires understanding definitions and selecting the right comparison method for the decision context.

Step-by-Step Solution:
1) Recognize that (a) refers to the mathematical toolkit (P/F, F/P, A/P factors, etc.).2) Note that (b) highlights the decision-making objective of choosing the most economical alternative.3) See that (c) emphasizes the need to master terminology and core concepts.4) The comprehensive statement is therefore (d) All of these.

Verification / Alternative check:
Standard textbooks structure chapters around terms, factors, and decision procedures, confirming the combined scope described.

Why Other Options Are Wrong:
Each of (a)–(c) is partially true but incomplete on its own; engineering economy is the union of these facets.

Common Pitfalls:
Applying a single metric inappropriately (e.g., IRR in mutually exclusive unequal-life projects without proper treatment); ignoring taxes or salvage; neglecting sensitivity analysis.

Final Answer:
All of these.