Arrange the electricity-generation pipeline from source to usage. Items: a. Electricity, b. Dam, c. Lights, d. River, e. Power House.

Introduction / Context:
Hydropower converts the potential energy of stored/channeled river water into electricity via turbines and generators in a power house. That electricity then powers end-use devices such as lights. The logical order must move from source to infrastructure to output to consumption.

Given Data / Assumptions:

• Source: River.
• Storage/Head: Dam.
• Conversion facility: Power House (turbine + generator).
• Output: Electricity.
• Load: Lights.

Concept / Approach:
A minimal causal chain is River → Dam → Power House → Electricity → Lights. Any order that powers lights before electricity is produced (or builds a dam before there is a river) is invalid.

Step-by-Step Solution:
(d) River provides flow and potential energy.(b) Dam creates head/control for generation.(e) Power House converts hydraulic energy to electrical energy.(a) Electricity is the deliverable.(c) Lights consume that electricity.

Verification / Alternative check:
Track energy transformation: hydraulic → mechanical → electrical → lighting (radiant output). The chosen option preserves this order.

Why Other Options Are Wrong:
They place consumption before generation (lights before electricity) or misplace the power house after usage.

Common Pitfalls:

• Treating “Dam” and “Power House” as interchangeable—only the house contains generation equipment.

Final Answer:
d, b, e, a, c.