Step 1: Recall the rate law form.
For a reaction of order $n$ in reactant A, $Rate=k[A]^n$. How the rate changes with time depends on this power $n$.
Step 2: Analyse a first order reaction.
Here $Rate=k[A]^1=k[A]$. As the reaction proceeds, $[A]$ keeps falling, so the rate also keeps falling with time. So Statement I is correct.
Step 3: Analyse a zero order reaction.
Here $Rate=k[A]^0=k$, a constant. The rate does not contain the concentration term at all.
Step 4: See the consequence for zero order.
Since the rate equals the constant $k$, it stays the same as time passes and does not decrease. So Statement II is incorrect.
Step 5: Combine the two findings.
Statement I (first order rate decreases with time) is true, while Statement II (zero order rate decreases with time) is false.
Step 6: Pick the matching option.
The combination true and false matches option (3).
\[ \boxed{\text{Statement I correct, Statement II incorrect (Option 3)}} \]