The correct answer is: D.C. motor.
A D.C. motor is a type of electric motor that uses direct current (DC) to power its rotor. DC motors are often used in applications where high starting torque and wide speed range control are required, such as in industrial machinery and power tools.
A single-phase capacitor start motor is a type of electric motor that uses a single-phase AC power supply. Single-phase capacitor start motors are often used in applications where low starting torque and a limited speed range are required, such as in fans and pumps.
An induction motor is a type of electric motor that uses alternating current (AC) to power its rotor. Induction motors are often used in applications where high starting torque and a wide speed range are required, such as in industrial machinery and power tools.
A synchronous motor is a type of electric motor that uses alternating current (AC) to power its rotor. Synchronous motors are often used in applications where high efficiency and a constant speed are required, such as in electric generators and variable-speed drives.
In conclusion, the correct answer is D.C. motor. D.C. motors are often used in applications where high starting torque and wide speed range control are required.