Petroleum exploration relies on surface clues and subsurface geoscience. Identify the most comprehensive detection approach for petroleum deposits, considering natural oil seepage observations, geophysical measurements (density, elasticity, magnetic and electrical properties), and knowledge of the age and nature of subsurface rocks.

Introduction / Context:
Finding petroleum accumulations requires integrating geology and geophysics. Early clues such as natural oil seepages guided initial drilling, but modern exploration depends heavily on geophysical surveys and stratigraphic/structural analysis to identify potential source, reservoir, and trap combinations. A robust detection strategy therefore blends multiple evidence streams rather than relying on a single indicator.

Given Data / Assumptions:

• Surface clues: natural seepages, bitumen shows.
• Geophysical data: gravity, seismic (elastic), magnetic, electrical methods.
• Geological context: rock age, depositional environment, and trap/seal presence.

Concept / Approach:
Hydrocarbon systems require source rock, maturation, migration pathways, reservoir porosity/permeability, trap, and seal. Surface seepage, while suggestive, may not align with drillable traps. Geophysical measurements detect density contrasts, elastic reflections, and magnetic/electrical variations associated with subsurface structure and lithology. Geological age and rock type indicate where source rocks and reservoirs likely occur. Synthesizing these lines of evidence yields the best chance of success.

Step-by-Step Solution:

Verification / Alternative check:
Exploration workflows universally integrate geological fieldwork, seismic interpretation, and potential field methods before committing to expensive exploratory wells.

Why Other Options Are Wrong:

Common Pitfalls:
Over-relying on seepage or a single geophysical anomaly without geological validation can lead to dry holes.

Final Answer:
All (a), (b) and (c)