Sure, let's analyze the pronunciation of the underlined parts in each group:

1. A. delta (underlined part: "e")
B. garage (underlined part: "a")
C. basement (underlined part: "a")
D. attention (underlined part: "a")

The word "delta" has a different vowel sound in the underlined part compared to the others. So, the answer is A. delta.

2. A. speaking (underlined part: "ea")
B. teaching (underlined part: "ea")
C. cleaning (underlined part: "ea")
D. wearing (underlined part: "ea")

The word "wearing" has a different vowel sound in the underlined part compared to the others. So, the answer is D. wearing.

3. A. farmers (underlined part: "s")
B. groups (underlined part: "s")
C. markets (underlined part: "s")
D. parks (underlined part: "s")

The word "groups" has a different consonant sound in the underlined part compared to the others. So, the answer is B. groups.

For the second part of the question:

Why did Dom send this message?
A. He is worried they'll miss some of the film.
B. He wants to eat something before the film.
C. He needs to tell Matt where the cinema is.

The message indicates that Dom and Ben are already at the cinema and are waiting for Matt. Dom mentions that the film starts soon and Ben wants to get some snacks, urging Matt to hurry up. This suggests that Dom is worried they might miss some of the film if Matt doesn't arrive soon.

So, the correct answer is A. He is worried they'll miss some of the film.