OmniScripts, DataRaptors, Integration Procedures, and FlexCards. This is the lowest-customization answer that still satisfies the business, security, and lifecycle requirements.
The Core Concept Explained: OmniStudio separates guided interaction, data mapping, orchestration, and UI presentation. That separation is critical for high-volume public-sector intake because each asset can be tested and reused independently.
Step-by-Step Technical Analysis: Design the user journey first, then decide which OmniStudio asset owns each responsibility. OmniScript captures guided input, DataRaptors map Salesforce data, Integration Procedures orchestrate server-side work, and FlexCards expose summarized context. After assembly, validate data payloads, error handling, security, and performance with realistic application records. Use OmniScripts for the guided form, DataRaptors for object read/write and transformations, Integration Procedures for orchestration and server-side processing, and FlexCards for summary or status views.
Why the Incorrect Options Are Wrong: A does not meet the implementation-quality bar for security, scale, auditability, or maintainability in this scenario. B does not meet the implementation-quality bar for security, scale, auditability, or maintainability in this scenario. D adds a custom build path and increases lifecycle, security, and upgrade effort when a packaged or declarative capability already supports the requirement.