The correct answer is: C. high speed TTL
Standard TTL is the slowest of
the TTL sub-families, followed by Schottky-clamped TTL, then low power TTL. High speed TTL is the fastest.Standard TTL is the original TTL logic family. It is relatively slow and consumes a lot of power.
Schottky-clamped TTL is a faster version of standard TTL that uses Schottky diodes to reduce switching time.
Low power TTL is a more power-efficient version of standard TTL. It is slower than Schottky-clamped TTL, but faster than standard TTL.
High speed TTL is the fastest of the TTL sub-families. It is used in applications where speed is critical, such as high-speed data transfer.