You plan to create an image that will contain a .NET Core application. You have a Dockerfile file that contains the following code. (Line numbers are included for reference only.) You need to ensure t

Question

Exhibits

Options

• A1
• B3
• C4
• D7

• A
  7% (4)
• B
  26% (16)
• C
  54% (33)
• D
  13% (8)

Explanation

Modifying line 4 matters because it is the second FROM statement in a multi-stage Dockerfile - the one that defines the final image. If it currently references mcr.microsoft.com/dotnet/core/sdk:2.2, it should be changed to mcr.microsoft.com/dotnet/core/aspnet:2.2 (or the runtime variant). The SDK image bundles compilers and build tooling that are unnecessary at runtime and add hundreds of megabytes; the aspnet image ships only the runtime, producing a much smaller deployable image.

Why the distractors are wrong:

• Line 1 (FROM sdk:... in the build stage) must stay as the SDK image - you need build tools to compile and publish the app.
• Line 3 is typically a COPY instruction for source files; changing it has no meaningful effect on the final image size.
• Line 7 is usually ENTRYPOINT or a late-stage instruction; it doesn't affect which base image layers are included.

Memory tip: Think of the two-stage pattern as "build big, ship small." The first FROM is your workshop (needs all the tools); the second FROM is your delivery box (only needs the runtime). Whenever a question asks about minimizing image size, look for the second FROM and confirm it uses aspnet or runtime, not sdk.

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