Which group of timber are available in quantity less than 335 m³ per year as per IS: 339-1963?

Correct option is C

Classification of Timber Based on Availability (Annual Outturn):
Grade X (Most Common): Availability of 1415 m³ or more per year
Grade Y (Common): Availability ranging from 355 m³ to 1415 m³ per year
Grade Z (Less Common): Availability of less than 355 m³ per year