Embryo of a seed is made up of

$\begin{array}{1 1}(A)\;\text{Meristematic tissue}\\(B)\;\text{Parenchyma}\\(C)\;\text{Collenchyma}\\(D)\;\text{Sclerenchyma}\end{array}$

Embryo is made up of specific embryonic meristem consisting of undifferentiated cells.
Hence (A) is the correct answer.