Delivery men with a false lead

1. There is no other permutation that meets that exact quota of falsehood.
2. There is exactly one false one (Beto's), as the statement requires.
3. Direct verification: Cora: “Ana arrived before Diego.” $1<2 \Rightarrow$ true.

Back to problem
Answer:

$$ \text{Ana},\ \text{Diego},\ \text{Beto},\ \text{Cora}. $$

Direct check:

• Ana: “I was first.” $\Rightarrow$ true.
• Beto: “Ana arrived immediately before me.”

Beto is 3rd and Ana is 1st $\Rightarrow$ false.

• Cora: “Ana arrived before Diego.”

$1<2$ $\Rightarrow$ true.

• Diego: “Beto arrived before Cora.”

$3<4$ $\Rightarrow$ true.
There is exactly one false one (Beto's), as the statement requires.
There is no other permutation that meets that exact quota of falsehood.