Passage: This designation was given to upgraded vehicles of the first batch of Leopard 2s, brought up to the standard of the second and third batches. This modernisation gradually replaced the original PZB 200 sights in the first batch with thermal sights for the EMES 15 as they became available. Furthermore, the upgrade included the fitting of filler openings and caps to the forward hull fuel tanks to allow separate refuelling, as well as the addition of a deflector plate for the periscope and a large coverplate to protect the existing NBC protection system. Finally, the tank was given new five metre towing cables with a different position. The programme began in 1984 and ended in 1987; the third, fourth and fifth batches, which were produced during this period, had the same features. The modernised first batch can be recognised by the circular plate covering the hole where the cross-wind sensor for the fire-control system was removed.

Question: What was the name of the tank upgraded with measures to allow separate refueling?
Leopard 2s