Which of the following option a declaration consist of?

The correct answer is: B. Property

A declaration is a statement that assigns a value to a property. A property is a named attribute of an element. For example, the following declaration assigns the value “red” to the “color” property of the element with the id “my-element”:

my-element {
color: red;
}

The other options are incorrect because:

• A tag is a markup element that defines a part of a document. For example, the following tag defines a paragraph:
  “`

This is a paragraph.

* A selector is a string that identifies a set of elements in a document. For example, the following selector selects all elements with the class "foo":
.foo {
color: red;
}
* A class is a named attribute of an element that can be used to group elements together. For example, the following element has the class "foo":

“`