[ A ] 4 

[ B ] 6  
[ C ] 8  
[ D ] 5 
[ A ] 4 

[ B ] 6  
[ C ] 8  
[ D ] 5 
Answer : Option D 
Explanation : 
1080 = $2 3$ $\times$ $3 3$ $\times$ 5. For any perfect square, all the powers of the primes have to be even numbers. So, if the factor is of the form $2^ a$ $\times$ $3^ b$ $\times$$ 5^ c$ . The values 'a' can take are 0 and 2, b can take are 0 and 2, and c can take the value 0. Totally there are 4 possibilities. 1, 4, 9, and 36. 
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