Step 1: Check each option
The slope at $(x_1,y_1)$ equals $x_1$, and it must be 1.
Step 2: Eliminate
Only $x_1=1$ is possible, which leaves the first option.
Step 3: Check
$1^2=2\cdot\dfrac12$, so the point lies on the parabola.
Final Answer:
Only (1, 1/2) lies on the curve and has slope 1.
\[ \boxed{\text{(A) }\left(1,\dfrac{1}{2}\right)} \]