Step 1: Read the clue carefully.
We are told the emf and the current touch zero together, reach their lowest together, and reach their highest together. We must name the circuit element.
Step 2: Turn the clue into one phrase.
If two wavy quantities rise and fall at exactly the same moments, we say they are in phase. So here voltage and current are in phase.
Step 3: Recall what a resistor does.
In a pure resistor the current follows the voltage with no delay. They are perfectly in phase.
Step 4: Recall what a capacitor does.
In a pure capacitor the current runs ahead of the voltage by a quarter cycle, so they are not in step. That does not fit.
Step 5: Recall what an inductor does.
In a pure inductor the current lags behind the voltage by a quarter cycle. Again they are out of step, so this is ruled out. A mix of inductor and capacitor gives some in-between lag too.
Step 6: Choose the match.
Only the resistor gives zero phase difference, so the element must be a pure resistor.
\[ \boxed{\text{pure resistor}} \]