“The elegy written in a country churchyard” is written in:

The correct option is Quatrains of ten syllable lines.

Thomas Gray's famous poem, "Elegy Written in a Country Churchyard", is written in a specific poetic form known as elegiac stanzas or heroic quatrains.
Let's break down this poetic structure step-by-step to understand why this option is correct:

1. Quatrains:
The poem is structured into stanzas of four lines each, which are called quatrains. The rhyme scheme of each quatrain is alternate, following an abab pattern.

2. Ten-Syllable Lines (Iambic Pentameter):
Each line in these quatrains is written in iambic pentameter. An iambic pentameter line consists of five metrical feet (iambs), where each foot contains an unstressed syllable followed by a stressed syllable. This structure results in exactly ten syllables per line.
For example, consider the opening line:
The cur-few tolls the knell of par-ting day
Counting the syllables: The (1) cur (2) -few (3) tolls (4) the (5) knell (6) of (7) par (8) -ting (9) day (10). This confirms it is a ten-syllable line.

Therefore, the poem is composed of quatrains containing ten-syllable lines.