If system x executes a program in $10$ seconds, and system Y executes the same program in $20$ seconds, this means that the speedup of system x over system Y is: A$.0\mathrm{.}5$ B$.2$ C$.1\mathrm{.}5$ If system x executes a program in $10$ seconds, and system Y executes the same program in $30$ seconds, this means that the performance improvement rate of x compared to Y is: A$.1$ B$.2$ C$.3$ If system x executes a program in $10$ seconds, and system Y executes the same program in $15$ seconds, this means that the reduction rate of the program execution time compared to Y is: A$.(1)/(2)$ B$.(1)/(3)$ C$.2$ Two computer systems, CompA and CompB, execute a program using the same instruction set architecture $($ISA$).$ If the clock cycle time in CompA is $250$ picoseconds and the