Final answer:
C) Data transfer. The cycle length in a single-cycle implementation must be long enough to support the data transfer instruction.
Step-by-step explanation:
In a single-cycle implementation, the cycle length must be long enough to support the data transfer instruction (probably load).
In a single-cycle implementation, each instruction takes one clock cycle to complete. The cycle must be long enough to allow for the slowest instruction, which is often a data transfer instruction like a load or store.
For example, if the processor is designed to support a maximum of 16-bit addresses, but a load instruction requires a 32-bit address, the cycle length must be long enough to handle the extra clock cycles needed to fetch the complete address.