Final answer:
Option c, "only a human brain can grasp" supports the idea that computers can't always complete translation work accurately.
Step-by-step explanation:
The detail from the text that best supports the idea that computers can't always complete translation work accurately is:
Option c: "only a human brain can grasp"
This statement suggests that computers may struggle to fully understand and grasp the nuances and complexities of language that a human brain can. While learning software may be able to accurately translate sentences, it is still limited in its ability to capture the subtleties and cultural context that are often integral to accurate translation.