Answer: c. Oxygen, silicon, and aluminium 
Explanation:
The common elements in the Earth's crust in order of decreasing abundance are as follows:  
Oxygen: Oxygen is the most abundant element on earth's crust. It makes up 46.6%. It exists as compound of the silicate minerals. It is used for industrial, commercial and medical purposes.
Silicon: Silicon is the second most common and abundant element on the earth crust. It makes up the concentration of 27.7%. It combines with the minerals of silica to form the silicate minerals. It is used for the purpose of ceramics, cosmetics, glass and other products.
Aluminium: Aluminium is the third most common and abundant element on the earth crust. It makes up the concentration of 8.1%. The aluminum exists in the form of aluminium oxide, potassium aluminium sulfate and aluminium hydroxide. It is used for the purpose of manufacture of rockets, machinery and automobiles.
 
        
                    
             
        
        
        
 Higher wages indicate a higher level of development because high salaries show that they have contributed their talents to the country's economy.
Explanation:
 
        
             
        
        
        
Igneous rock are formed by the cooling and crystallization of molten rock and are formed by the cooling of magma above earth's surface.
Let's look into the statements one by one: 
 Igneous rocks are formed only from material ejected during a volcanic eruption.
-This is not true because igneous rock can also be formed by the cooling down of magma inside a volcano or magma that was trapped in the crack of crust.
Igneous rocks are formed by the cooling and crystallization of molten rock.
-This is correct.
Igneous rocks are produced by the weathering and transport of pre-existing rocks.
-This is incorrect as igneous rock is formed by volcanism. The rock that are formed with the statement is sedimentary rock.
Igneous rocks are formed by the cooling of magma above earth's surface and lava below the surface.
-This is correct. Both intrusive and extrusive volcanic activity forms igneous rock after cooling down.
Igneous rocks are formed by recrystallization
-This is not true as recrystallization does not take place in the formation of the igneous rock. The rock formed by recrytillization is metamorphic rock.
Therefore,the igneous rock are formed by the cooling and crystallization of molten rock and are formed by the cooling of magma above earth's surface.
Hope it helps!
 
        
             
        
        
        
It’s known as a composite volcano 
Dude on top is right^^
        
                    
             
        
        
        
C. Fishing
I think fishing would make sense due to living in a river valley.