Which sentence is irrelevant to helping the author support his claim?

A.
"Calligraphy will always be available on computers and on display in museums."
B.
"Computers can actually keep calligraphy alive through the abundance of digital fonts that are available."
C.
"Word processing has changed writing into a quick procedure that allows almost any writer to eliminate basic spelling and grammar errors."
D.
"Along with that, people really shouldn't fear that the dwindling use of calligraphy and other detail-driven penmanship forms will impact fine motor skills."

A. "Calligraphy will always be available on computers and on display in museums."

The sentence that is irrelevant to helping the author support his claim is: "Calligraphy will always be available on computers and on display in museums."

To determine which sentence is irrelevant to helping the author support his claim, we need to first identify the author's claim. Upon reviewing the given sentences, the author's claim seems to be focused on how computers and digital fonts are helping to keep calligraphy alive.

With this claim in mind, we can analyze each sentence option:

A. "Calligraphy will always be available on computers and on display in museums."
This sentence supports the claim by highlighting the availability of calligraphy on computers, which aligns with the argument that computers are helping keep calligraphy alive.

B. "Computers can actually keep calligraphy alive through the abundance of digital fonts that are available."
This sentence directly supports the claim by stating how computers and digital fonts contribute to keeping calligraphy alive.

C. "Word processing has changed writing into a quick procedure that allows almost any writer to eliminate basic spelling and grammar errors."
Although this sentence discusses the impact of word processing on writing, it does not directly contribute to supporting the claim about how computers and digital fonts keep calligraphy alive. It can be seen as irrelevant in this context.

D. "Along with that, people really shouldn't fear that the dwindling use of calligraphy and other detail-driven penmanship forms will impact fine motor skills."
Although this sentence discusses the impact of the dwindling use of calligraphy, it does not directly contribute to supporting the claim about how computers and digital fonts keep calligraphy alive. It can be seen as irrelevant in this context.

Therefore, sentence C is the one that is irrelevant to helping the author support his claim about the role of computers and digital fonts in keeping calligraphy alive.