A $250 V$ dc shunt motor has an armature resistance of $0.2\:\Omega$ and a field resistance of $100\:\Omega$. When the motor is operated on no-load at rated voltage, it draws an armature current of $5 \: A$ and runs at $1200 \: rpm$. When a load is coupled to the motor, it draws total line current of $50 \: A$ at rated voltage, with a $5 \%$ reduction in the air-gap flux due to armature reaction. Voltage drop across the brushes can be taken as $1 V$ per brush under all operating conditions. The speed of the motor, in $\text{rpm}$ under this loaded condition, is closest to:
- $1200$
- $1000$
- $1220$
- $900$