Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the option that best fits each of the numbered blanks from 18 to 22.

The Metro Line No. 1 (Ben Thanh - Suoi Tien) in Ho Chi Minh City ___(1)___. The 61.5-meter-long train started from the underground Ben Thanh Station, passing through 11 elevated stations and 3 underground stations, and ended its journey at Suoi Tien Station near the new Mien Dong Bus Station in Thu Due City. This marks the first full-line test run following internal technical inspections carried out by the contractor, Hitachi from Japan.
The trial run was divided into three phases, starting at 9:15 AM and concluding at 12:20 PM. During the first phase, the train departed from Ben Thanh Station and stopped at Ba Son Station ___(2)___. It then continued through elevated stations such as Tan Cang and An Phu before returning to the starting point.
The test run attracted significant attention, offering a glimpse into the near-completed metro project. ___(3)___. The Metro Line No.1 project is expected to be operational soon, promising to transform the daily commute for thousands of residents.
This milestone trial highlights not only the project's technical readiness but also public anticipation for a modern, efficient transit system. Equipped with state-of-the-art technology and advanced safety features, ___(4)___. However, challenges such as ensuring seamless integration and maintaining consistent operations will be critical as the system approaches its official launch. ___(5)___.