{“Personas”: [{ {“id”: 0,“name”: “Miguel Sanchez”,“age”: 306,},{“id”: 1,“name”: “Juan Perez”,“age”: 20,}}]}

[{“id”: 0,“name”: “Miguel Sanchez”,“age”: 306,},{“id”: 1,“name”: “Juan Perez”,“age”: 20,}]

http.get('assets/inhabitants.json')
  .subscribe((response: Response) => {
    console.log(response);
  });

{“Personas”: [{ {“id”: 0,“name”: “Miguel Sanchez”,“age”: 306,},{“id”: 1,“name”: “Juan Perez”,“age”: 20,}}]

{"Personas": [{ {"id": 0,"name": "Miguel Sanchez","age": 306,},{"id": 1,"name": "Juan Perez","age": 20,}}]}

http.get('/assets/inhabitants.json').subscribe((response: Response) => {
    let personas = response.json().Personas;
    console.log(personas); // devolveria lo que solicitas.
});

{"Personas": {[...]} }

{"Personas": [...]}

http.get('assets/inhabitants.json')
  .subscribe((response: Response) => {
    console.log(JSON.parse(response).Personas);
  });