Falcon will be the best. Falcon need 36,5 sec for 2000 m, so 1 transport last 93 sec. As it need 7 times for delivery of 25 tons total time will be 594,5 sec. Falcon has go 6 times full route and seventh time only need 36,5 sec.
Rino need to go 9 times and need 47,9 sec for 2000 m. It is automatically worse than Falcon.
Boar need 63,2 sec for 2000 m. As Boar need to go 5 times total time is 648,8 sec : 9x63,2+4x20 sec.