We aren't liking the font for either #1 or #3. It comes across a bit childish.
The apple for entry #1 also seems to relate more towards grade school level children. The platform will be for career adults within the oil and gas industry.
The DK brain idea for entry #3 could be a cool concept, but again it's current implementation seems to rounded and playful. It's also hard to distinguish the "D" and "K" letters within the icon.