Mature seeds of plants such as gram and pear possess no endosperm because

Question

$\begin{array}{1 1} \text{a. These plants are not angiosperms} \\ \text{b.There is no double fertilization in them} \\ \text{c. Endosperm is not formed in them.} \\ \text{d. Endosperm gets used up by developing embryo directly during seed development.} \end{array} $