I did not understood by metal required in cubic meter for this road.
Metal - called for reinforcement steel or Aggregates.
I consider it as a typing mistake and consider it as a material or concrete required in cubic meters.
so the general volume calculation formula is length x width x height or depth.
here you have length of 1km = 1000 meters
width = 3.7 meter
depth or height = 8 cm = 0.08 meter
we have now converted all measurements to meter
now calculate the quanitity
concrete / material in cum required = 3.7 x 0.08 x 1000
= 296 cum (It matches to option A from your uploaded question picture)
I may be wrong in understanding it, take another person opinion too on it.
Also request you to not to upload such heavy size pictures, compress it to 100 to 300kb before posting, it will help us to get load faster.