1. Correct Answer: C: Only three
 
 2. Explanation of Statements/Options:
 
     ● Statement I: Cobalt  
           ○ Cobalt is a key component in many lithium-ion battery cathodes.
           ○ It is used to improve energy density and stability.
           ○ Cobalt helps in extending the life of the battery.
           ○ Therefore, cobalt is commonly found in battery cathodes.
 
     ● Statement II: Graphite  
           ○ Graphite is typically used in the anode, not the cathode, of lithium-ion batteries.
           ○ It serves as the host for lithium ions during charging and discharging.
           ○ Graphite is crucial for the battery's performance but is not part of the cathode.
           ○ Therefore, graphite does not usually make up battery cathodes.
 
     ● Statement III: Lithium  
           ○ Lithium is a fundamental element in lithium-ion batteries.
           ○ It is used in the cathode material to store and release energy.
           ○ Lithium is essential for the battery's operation and is part of the cathode.
           ○ Therefore, lithium is commonly found in battery cathodes.
 
     ● Statement IV: Nickel  
           ○ Nickel is often used in the cathode of lithium-ion batteries.
           ○ It helps increase the energy density and capacity of the battery.
           ○ Nickel is a critical component for high-performance batteries.
           ○ Therefore, nickel is commonly found in battery cathodes.
 
 In summary, cobalt, lithium, and nickel are typically used in battery cathodes, while graphite is used in the anode. Hence, the correct answer is C: Only three.