2 of Spades: There's only one 2 of spades card in the deck, so the probability of choosing the 2 of spades is 1/52.
A Jack: There are 4 Jacks in the deck, so the probability of choosing a jack is 4/52, or 1/13.
A red King: There are 2 red kings in the deck, so the probability of choosing one is 2/52, or 1/26.
A Diamond suit: There are 13 diamond cards in the deck, so the probability of choosing one is 13/52, or 1/4.