Select the most appropriate option that can substitute the underlined segment in the given sentence.
‘Spy Family’ is a graphic novel that is a narrative work in which the story is conveyed to the reader using uninterrupted art in a traditional comics format.

The correct option is sequential art in a traditional.

Step-by-step Explanation:
1. Analyze the underlined segment: The sentence describes the medium of a graphic novel as a narrative work where the story is conveyed using "uninterrupted art in a traditional comics format." We need to choose the option that uses the most appropriate and standard terminology to describe this artistic medium.
2. Define the standard term: The term sequential art is the recognized academic and industry term used to define comics and graphic novels. Coined by legendary cartoonist Will Eisner, it describes an art form that uses a sequence of images (or panels) juxtaposed in a specific order to convey information and/or produce an aesthetic response in the viewer.
3. Evaluate the given options:
- sequential art in a traditional: Correct. This accurately substitutes the description with the correct artistic term.
- sedimental art in a traditional: Incorrect. "Sedimental" refers to sediment or geological layers, which has no relevance to visual art formats.
- longitudinal art in a traditional: Incorrect. "Longitudinal" relates to length or direction, which is not a term used to describe comic formats.
- existential art in a traditional: Incorrect. "Existential" relates to philosophy and human existence, which does not define the structural format of comic book panels.
4. Conclusion: Therefore, "sequential art in a traditional" is the most appropriate and precise substitution for the underlined phrase.