Mendel published his work on inheritance of characters in $1865$ but it remained unrecognised till $1900$ because

$(a)$ He could not provide any physical proof for the existence of factors

$(b)$ His concept of factors as stable, discrete units that controlled the expression of traits did not find acceptance from the contemporaries

$(c)$ Mendel's approach of using mathematics to explain biological phenomena was totally old

$(d)$ Communication was not easy (as it is now)

• A

  $(a), (b) \;\& \;(c) $are correct

• B

  $(c) \;\& \;(d)$are correct

• C

  $(a), (b) \;\&\; (d)$ are correct

• D

  Only $(a)$ is correct