6.

Answer and Explanation

Your Answer is

Correct Answer is H

Explanation

Item H: The past participle of designed is used as a post-attributive and modifies kiln.

Item F/G: Before the underlined part is a complete sentence, and the underlined part is not guided by a conjunction, so it cannot be a complete sentence after it.

Item J: As a countable noun, Brick needs to add the article a/the to satisfy grammatical correctness.