Q:Information: - The Massif des Calanques is a wild and rugged terrain stretching from the ninth arrondissement of Marseille to the east towards Cassis , spanning 20 km in length and 4 km in width along the coast . Its highest peak is Mont Puget at 565m . This is one of France 's great natural beauty areas . - Limestone is a sedimentary rock, composed mainly of skeletal fragments of marine organisms such as coral, forams and molluscs. Its major materials are the minerals calcite and aragonite, which are different crystal forms of calcium carbonate (CaCO). - Pierre Puget (16 October 1620 2 December 1694) was a French painter, sculptor, architect and engineer. - Mont Puget, named after the French sculptor Pierre Puget, is a mountain, part of Marseille-Cassis calanques, located south-east of Marseille. Like most Marseille mountains, it is formed from limestone. - Cassis (Occitan: "Cassis") is a commune situated east of Marseille in the department of Bouches-du-Rhone in the Provence-Alpes-Cote d'Azur region in southern France. Given the information above, choose from the list below the object entity that exhibits the relation 'instance of' with the subject 'massif des calanques'. Choices: - architect - commune - crystal - december - limestone - mountain - october - part - region
A:
mountain