Select the most appropriate option that can substitute the underlined segment in the given sentence.
He takes his always dog for a walk in the park.

The correct option to substitute the underlined segment is always takes his dog for a walk.

Explanation:

In English grammar, adverbs of frequency (such as always, never, often, usually, sometimes) are placed before the main verb of the sentence. In the given sentence, the main verb is "takes". Therefore, the adverb "always" must be placed directly before "takes".

Let's analyze the positioning:

1. Incorrect placement: "takes his always dog" (puts the adverb inside the noun phrase "his dog", which is grammatically incorrect).

2. Correct placement: "always takes his dog for a walk" (places the adverb of frequency "always" before the main verb "takes").

Thus, the grammatically correct sentence is:

"He always takes his dog for a walk in the park."