The correct option is B Von Baer
Von Baer (1828) proposed recapitulation theory which was revised and renamed by Haeckel's biogenetic law. According to the theory, all organisms recapitulate evolutionary history of their race in abbreviated form during their development. This makes option B correct.
Haeckel (1868) proposed biogenetic law which states that ontogeny repeats phylogeny. Here, ontogeny refers to life history of an individual and phylogeny is the history of evolution of the individual. Option A is incorrect as Haeckel modified the theory originally given by Von Baer.
Malthus, in Malthus’s essay on human population, proposed that living organisms multiply in geometric ratio. Option C is incorrect.
Weismann refuted the Lamarck’s theory of inheritance of acquired characters by his “rat experiment” and proposed the theory of continuity of germplasm which states that only germplasm is inherited to next generation, not the somatoplasm. Option D is incorrect.
Therefore, the correct answer is option B.