The correct answer to this open question is the following.
Although there are no options attached we can say the following.
What he meant by 'present mixed and confused' phenomena was that there are good situations or events presented on a daily basis as well as negative situations and occurrences presented daily. And humans have to deal with them properly.
That is why he wrote that people "must prove these pure unmixed, and uncontrollable attributes from the present mixed and confused phenomena, and from these alone."
We are talking about Scottish philosopher David Hume's ideas on religion expressed in his book "Dialogues Concerning Natural Religion," written in 1779.
In this work, Hume created three characters/philosophers named Cleanthes, Philo, and Demea, whose ideas analyze the existence of God.