Which of the following is the best way to combine the independent and dependent
clause to make it a complex sentence?
Dad shook his head no.
who worked in a circus many years ago.
O
A. Dad shook his head no after he had worked in the circus many years ago.
O
B. Dad shook his head no, and he had worked in the circus many years ago.
O
C. Dad shook his head, he had worked in the circus many years ago, no
O
D. Dad, who had worked in the circus many years ago, shook his head no.

The answer to your question would be sentence D.

Explanation:

The best way to combine the independent and dependent clause to make it a complex sentence is as shown in sentence D. A complex sentence is a sentence that contains an independent clause and one or more dependent clauses.  An independent clause, as opposed to a dependent one, can stand alone as a sentence as it represents a complete thought (see 1). (1) is not an independent clause as it fails to stand alone as a complete sentence, it depends on the main (dependent) clause to complete its meaning (see 2).

1) *Who had worked in the circus many years ago

2) Dad shook his head no

they bound logs together and built a raft. enkidu steered it down the great river. gilgamesh carried humbaba's head.