TRy this array formula

=SUM(IF(FREQUENCY(IF(($A$1:$A$15<>"")*($B$1:$B$15="Active")*($C$1:$C$15="a" ),
MATCH($A$1:$A$15,$A$1:$A$15,0)),ROW(INDIRECT("1:"&ROWS($A$1:$A$15))))>0,1))

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