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A Naked Pair is a Naked Subset of size 2.
It is formed by 2 cells that have candidates for only 2 digits and are collocated in the same house.
Pay attention to the cells r1c7 and r3c7 (highlighted in yellow) in the 7th column, which only have the two digits 5 and 6 as candidates. Therefore, the digits 5 and 6 must go into these two cells. This means that 5 and 6 can be eliminated in the remaining cells in the 7th column, so r6c7<>5 and r7c7<>6.
Incidentally, the r1c7 and r3c7 are also collocated in the same box, which is the 3rd one. Using the same logic leads to r1c9<>5, r1c9<>6 and r3c8<>6.