Law of limiting factors was given by
a)	Leibig	b)	Blackman	c)	Calvin	d)	Arnon

(b)

Blackman (1905) extended the law of minimum to formulate the law of limiting factors, which in his own words is ‘when a process is conditioned as to its rapidity by a number of separate factors, the rate of the process is limited by the pace of slowest factor.’