Let a₁,a₂,a₃,⋯,a₁₀ be in G.P. with ai>0 for i=1,2,⋯,10 and S be the set of pairs (r,k),r,k∈N (the set of natural numbers) for which
|logₑ aʳ₁aᵏ₂ logₑ aʳ₂aᵏ₃ logₑ aʳ₃aᵏ₄|
|logₑ aʳ₄aᵏ₅ logₑ aʳ₅aᵏ₆ logₑ aʳ₆aᵏ₇|
|logₑ aʳ₇aᵏ₈ logₑ aʳ₈aᵏ₉ logₑ aʳ₉aᵏ₁₀|
Then the number of elements in S, is :
A. 2
B. 4
C. 10
D. infinitely many