Answer
A
Work Step by Step
a) true, 4s: $n+\ell=4$; 4p: $n+\ell=5$
b) false, 5d: $n+\ell=7$; 6s: $n+\ell=6$
c) false, 3d: $n+\ell=5$; 3p: $n+\ell=4$
d) false, 4f: $n+\ell=7$; 5p: $n+\ell=6$
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