Consider the following code and answer the following question

$//$ Interface

interface Engine $\{$

void start$()$;

void stop$()$;

$\}$

abstract class Vehicle $\{$

private Engine engine;

public Vehicle$($Engine engine$)\{$

this.engine $=$ engine;

$\}$

public void startEngine$()\{$

engine.start$()$;

$\}$

public void stopEngine$()\{$

engine.stop$()$;

$\}$

$//$ Other common vehicle methods

$\}$

class Car extends Vehicle $\{$

private String model;

public Car$($String model, Engine engine$)\{$

super$($engine$)$;

this.model $=$ model;

$\}$

$//$ Car$-$specific methods

$\}$

class Bike extends Vehicle $\{$

private String type;

public Bike$($String type, Engine engine$)\{$

super$($engine$)$;

this.type $=$ type;

$\}$

$//$ Bike$-$specific methods

$\}$

interface ElectricVehicle extends Engine $\{$

void charge$()$;

$\}$

class ElectricCar extends Car implements ElectricVehicle $\{$

public ElectricCar$($String model$)\{$

super$($model$,$ null$)$; $//$ Engine can be null for electric cars

$\}$

@Override

public void charge$()\{$

$//$ Charging logic for electric cars

$\}$

$\}$

Which one of the following answers are incorrect $($Please check all that apply$)$:

a$.$

A composition relationship exists between Car and Vehicle

b$.$

ElectricVehicle is a subclass of Engine

c$.$

Engine is a subclass of Vehicle

d$.$

Class Vehicle realizes the interface Engine

e$.$

ElectricVehicle is realized by ElectricCar

f$.$

Bike is a subclass of Engine