According to IS 287: 1993, in classifying timber, the average annual relative humidity (%) of Zone IV region of India is more than:

Correct option is B

 As per IS 287 (1993): The permissible moisture content for timber used for different purposes recommendations
ZONES
 The country has been broadly divided into the following four zones on the basis of seasonal changes in the moisture content of timber at 12 localities in India.
 Zone I- Average annual relative humidity less than 40 percent.
 Zone II- Average annual relative humidity 40-50 percent.
 Zone III- Average annual relative humidity above 50 and up to 67 percent. 
 Zone IV- Average annual relative humidity of more than 67 percent.