The typical time taken to freeze seafood to -18°C in a cryogenic freezer using liquid nitrogen is:

Correct option is B

Cryogenic freezing is an ultra-fast freezing method that uses extremely low-temperature substances like liquid nitrogen (-196°C) or liquid carbon dioxide to quickly bring down the temperature of food products.
For seafood, which is typically delicate and sensitive to structural damage, cryogenic freezing is used to minimize ice crystal formation, preserving texture and quality.
The process rapidly freezes the product to -18°C or lower, typically within 2 to 5 minutes, depending on product size and shape.
Why not other options?
30 sec to 1 min: Too short for most seafood pieces unless extremely small.
15–25 minutes: These durations are typical for conventional blast freezers, not cryogenic freezers.
Hence, the correct answer is Option (b).