well dude i can tell you how i u$ed to under$tand the$e..
for your ease you can just rotate the picture anticlockwise 90 degrees as we prefer to see capacitor's plate vertically..
you will get a view like this..
you can assume those two vertical lines to be the capacitor's plates
here u can ea$ily see that these two dielectrics are in parallel and can now be re distributed as the 2 in parallel..
i think now u can solve your question easily..
rotate it by 90 degrees and you can see that k2 and k3 are connected in series and k1 is in parallel with both of them..
just give it a try now..
Hope it helps :D