The answer is D) Higher link length and Higher transmission rate.
Why?
- Its high link length, as if link is short the propagation delay will be less → high link utilization.
- Its higher transmission rate, as if transmission rate is high, less time(useful time) is used in actually sending the data, If we have low transmission rate, we need more time to actually send the data (useful time).
example: tp = 100s
B=1) 10bps 2) 100 bps
Data = 200 bits
In first case link utilization: 20/120 => 1/6 (higher)
In second case: 2/102 = 1/51 (lower)
Silly mistake, which I made during exam: considering transmission time instead of transmission rate.