Ok, so “is” is the linking verb and I’m pretty sure the predicate is... effective? I’m not sure tbh! But I really do think it is that. I’m sorry if it is incorrect. My apologies.
D is well worded and has more detail. id go with D.
Graphic organizers are visual and graphic displays that organize ideas and demonstrate relationships between different information and concepts. They are designed to improve learning outcomes for students, review information, and are especially helpful to students who struggle with arranging information.
this is what I found online..not sure if it helps but here
