Ans will be A)
Average instruction time is measured by throughput of a processor.
Now we know, pipeline processor definitely decreases avg instruction time. But it's throughput increases.
Now, throughput measured by rate of which instruction instruction execution is completed. Any time one of the stages in pipeline cannot complete it's operation in one clock cycle, the pipeline stalls and degradation of performance occurs, So, when no. of stages increase, avg. instruction time also increase.
But avg. decreases the time, when the number of individual instruction is more. But it definitely not inversely proportional to size of program. Though time requires is less in execution of avg. instruction, with individual instruction execution time
So, ans will be A)