A

Step 1: Let's analyze each option in Column-I and match it with the corresponding option in Column-II based on the principles of electrical circuits, specifically focusing on series RL circuits.

(i) To increase current in a series RL circuit:
In a series RL circuit, the current can be increased by decreasing resistance (R). According to Ohm's Law, $I = \frac{V}{R}$, if we decrease R while maintaining a constant voltage (V), the current (I) will increase.
Thus, the match is (i) - [A] decrease R.

(ii) To increase phase angle in a series RL circuit:
The phase angle \(\phi\) in a series RL circuit is given by $\tan(\phi) = \frac{X_L}{R}$, where $X_L$ is the inductive reactance. To increase the phase angle, we can increase the resistance R. Therefore, the match is (ii) - [B] increase R.

(iii) To decrease the phase angle in a series RL circuit:
Again using the relation $\tan(\phi) = \frac{X_L}{R}$, to decrease the phase angle, we should decrease the resistance R or increase the inductance (or frequency, since $X_L = 2\pi f L$). Increasing the frequency results in a reduction of effective impedance (phase angle). Hence, the match is (iii) - [C] increase frequency.

(iv) To decrease the current in a series RL circuit:
To decrease the current, we can increase resistance R or even connect a capacitor in series which will oppose the current flow further. Therefore, the match is (iv) - [D] connect C in series.

Final Matches:
(i) - [A]
(ii) - [B]
(iii) - [C]
(iv) - [D].

Based on the analysis, the correct answer option is A.