CompTIA Network+

Answer: D -An OC-1 link offers 51.48 Mbps, a T1 line offers 1.544 Mbps, a T3 line offers 44.736 Mbps, and an ISDN PRI offers 1.544 Mbps.

Key Takeaway: Optical carrier classifications are based on the abbreviation OC followed by a number specifying a multiple of 51.84 Mb it/s (i.e., n × 51.84 Mb it/s). For example, OC-1 is a SONET line with transmission speeds of up to 51.84 Mb it/s, payload of 50.112 Mb it/s, and overhead of 1.728 Mb it/s.