Alice is in a special situation where she cannot discard.
Bob's blue 4 has been previous touched with a blue clue.
Cathy's red 2 and yellow 2 have previously been touched with a number 2 clue.
Enumerate all of the legal Tempo Clues that Alice can give.
Alice could give a Tempo Clue to the blue 4 in Bob's hand:
A number 4 clue would be legal, since it would only touch slot 4. This would "fill-in" the 4 to be a blue 4.
A blue clue would be legal, since it would only touch slot 4. This would not "fill-in" the card, but the clue would still mean to "play the card", so it would still work properly.
Alice could give a Tempo Clue to the red 2 in Cathy's hand:
A number 2 clue would not be legal, since it would focus slot 1 instead of slot 4.
A red clue would be legal, since it would only touch slot 4.
Alice cannot give a Tempo Clue to the yellow 2 in Cathy's hand:
A number 2 clue would not be legal, since it would focus slot 1 instead of slot 5.
A yellow clue would not be legal, since it would focus slot 3 instead of slot 5.