What are the 3 main river systems in the middle east?
a) the seine, the thames, and the nile.
b) the amazon, orinoco, and euphrates.
c) the nile, the zambezi, and the tigris.
d) the tigris, euphrates, and nile.

D) the Tigris, Euphrates, and Nile 
Those are the only rivers listen that are in the middle east 

The 3 main river systems in the middle east are  ,the Tigris, Euphrates, and Nile
because middle east is the mountainous and the hilly and the large area of it contain deserts and its major cities and town located on river   
So in my opinion opinion D is correct

True as the lakes are a marine body. also there's no difference in lake and ocean except for the size.

It should be a because the dilation changes the sides but not angles because in all shapes you have a certain degree number to add up to like for example a triangle is always 180 degrees