Right choice is (a) True
The explanation: More recently, an improved version has been designed and marketed by Aeroweld Industries, B-9 HAL Industrial Estate, Bangalore – 560 037. The size of the blocks is 30.5 cm x 14.4 cm x 10 cm or 23 cm x 19 cm x I0 cm. One such machine can be utilised to make 300 – 500 blocks per day by four unskilled workmen.