Which among the following is incorrect about arrangement of cells in embryo?

• A. The word blasted derives its origin from the word blastula which means a hollow ball of cells formed during the early stage of embryo
• B. If the number of cell layers in blastula is two in number, i.e. ectoderm and endoderm, then such organisms are considered to diploblastic
• C. If the number of cell layers in blastula is three in number, i.e. ectoderm, mesoderm and endoderm, then such organisms are considered to triploblastic
• D. In diploblastic organisms, mesoglea, a well differentiated substance, is present between endoderm and ectoderm