vertically upwards the force on the base of the tank

Question

A rectangular tank of base size 3m by 3m  contains oil of specific gravity 0.8 upto a height of 8 m. When it is accelerated at  2.45 m/s² vertically upwards the force on the base of the tank will be

(a) 29400 N         (b) 38240 N         (c) 78400 N        (d) 49050 N