1. Probability that Carlos is selected first = 1/14

2. Now that Carlos is out of the selection pool, the probability that Minerva is selected next is 1/13.

3. Now that Carlos and Minerva are out of the selection pool, the probability that Rafael is next is 1/12.

4. Now that Carlos, Minerva and Rafael are out of the pool, the probability that Yolanda is next is 1/11

5. These are all independent probabilities, so we can multiply them to get the chance that all four events take place

(1/14)(1/13)(1/12)(1/11) = 0.0249750%