Each of the following items contains a set of sentences. Read them carefully and identify the sentence that has a grammatical or contextual error. If all the sentences are error-free, select the "all are correct" option.

The correct option containing a grammatical error is:
"Age is a merely figure to 78-year-old sprinter Haruo Miyamoto, who is a proud member of the Osaka Sunrise Athletics Club."

Explanation:
In this sentence, the word merely is an adverb, but it is incorrectly used to modify the noun figure. An adjective is required to modify a noun.

The adverb "merely" should be replaced with the adjective "mere", or the word order should be adjusted (e.g., "Age is merely a figure..."). In the phrase "a merely figure", using "merely" directly before the noun "figure" is grammatically incorrect. Therefore, this sentence contains a grammatical error.

All other given options are grammatically and contextually correct.