The best answer to fill in the blank (5) is B) is intrigued.
The correct sentence would then read: "Although he began his life apprenticing to a goldsmith, Gutenberg is intrigued by the printmaking process."
This choice maintains the present tense, making it a more dynamic statement about his ongoing feelings. The other options suggest past tense, which does not align with the introductory clause that suggests a connection between his past and present intrigue.