Answer:
A letter to a politician that sounds supportive but sarcastically
criticizes his policies, is an example of Juvenalian satire.
Explanation:
Juvenalian satire is one of the type of satire in literature which means an ironic criticism of any contemporary leader, person, or any organization.
The sentence, ‘A letter to a politician that sounds supportive but sarcastically criticizes his policies’ is the definitely a juvenalian satire. In the sentence ironic criticism is made on the politician, on one hand the letter sounds supportive, but on the other hand the same letter consist of words criticizing his work and his policies.