What is the optimized version of the relation algebra expression πA1(πA2( σF1(σ F2(r)))), where F1, F2 are sets of attributes in r with F1 ⊂ F2 and F1, F2 are Boolean expressions based on the attributes in r?
1
πA1(σ(F1 ⋀ F2)(r))
2
πA1(σ(F1 ⋁ F2)(r))
3
πA2(σ(F1 ⋀ F2)(r))
4
πA2(σ(F1 ⋁ F2)(r))
5
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