how is this not at least an s- ???

Farm. I can't see the game time, because you cut it out, but I would assume that the game went to at least 33-ish minutes, from the Ziggs' farm.

Farm is a huge part of the grading system, and as a general goal, you want to aim for 10 cs/min, so in a 35 minute game like that one, you should have had 350 CS.

I would imagine you got an A or an A+ for that game, no? Just practice farming, take toucans whenever they're up, etc etc. It really helps.

Farm, from what I can tell you appear to have gotten yourself into a 35 min + game. Having such little far will do it. Also, damage numbers and number of deaths will do that. Draven tends to do high burst but less sustained damage, which leads to claiming kills, but not doing tons of damage, not that it isn't possible you did a lot of damage. You also died 13 times, which is second most on your team. As an ADC, you need to die less in order to receive higher ratings.

29 kills looks like a lot. Until you realize you died fucking 13 times. Which is WAY too much.

And given that it is probably a 40+ minute game, your farm is too low (not by a lot, but it is low).