Explanation:

Let’s break it down:

- ‘Picture’ is something you *colour*. That’s the action or quality you often give to a picture.

- So, we’re looking for: ‘Letter’ is something you...? Which word below relates to how you can treat or present a letter?

Option 1: Bold

- To ‘bold’ a letter is to change its appearance, but not every letter is bold.

- Just like not every picture is coloured—but colouring applies naturally to pictures in general, while bold doesn’t apply naturally to letters in general.

Option 2: Alphabet

- An alphabet is a collection of letters, but it’s not an attribute or quality of a letter.

Option 3: Word

- Words are made of letters, but that’s not a change or quality applied to a letter.

Option 4: Language

- Language is made up of words and letters, but again, not a direct quality or attribute.

Here’s what this really means:

The relationship is about an attribute you can give: you can ‘colour’ a picture, you can make a letter ‘bold’.

So, the answer is:

Option 1: Bold