Identify the poems termed as “pastoral elegies”:
[A] Lycidas
[B] In memory of W.B. Yeats
[C] Adonais
[D] Thyrsis
[E] In memoriam
Choose the most appropriate answer from the options given below:

The correct option is A, C and D only.

To understand why this option is correct, we must analyze the definition of a pastoral elegy and examine each poem mentioned in the options:
A pastoral elegy is a poem that uses the classical conventions of pastoral poetry (featuring shepherds, rustic life, and rural landscapes) to express grief and mourn the death of a friend or a beloved figure.

Let us evaluate each of the given poems:
1. [A] Lycidas: Written by John Milton in 1637, this is one of the most famous pastoral elegies in the English language. It was written to mourn the death of Milton's classmate, Edward King, who drowned at sea. In the poem, Milton represents himself and King as companion shepherds guarding their flocks.
2. [B] In Memory of W.B. Yeats: Written by W. H. Auden in 1939, this is a modern elegy written upon the death of the Irish poet William Butler Yeats. Unlike classical pastoral elegies, Auden rejects pastoral conventions, using instead realistic, cold, and urban imagery to reflect on Yeats's death and legacy.
3. [C] Adonais: Written by Percy Bysshe Shelley in 1821, this is a major pastoral elegy written to mourn the death of the poet John Keats. Shelley borrows heavily from classical Greek models (such as Bion and Moschus) to elevate Keats to the status of a mythological shepherd figure, Adonais.
4. [D] Thyrsis: Written by Matthew Arnold in 1865, this poem is a pastoral elegy composed in memory of his friend, the poet Arthur Hugh Clough. Arnold uses the pastoral setting of the Oxford countryside and portrays himself and Clough as rustic shepherds (Thyrsis and Corydon).
5. [E] In Memoriam: Written by Alfred, Lord Tennyson in 1850, this is a monumental elegy written to mourn the death of his close friend Arthur Henry Hallam. Although it is a deeply reflective and philosophical work focusing on grief, faith, and science, it does not employ pastoral conventions (such as depicting the characters as shepherds or using traditional rural metaphors), and is therefore not categorized as a pastoral elegy.

Based on the analysis, Lycidas (A), Adonais (C), and Thyrsis (D) are classified as pastoral elegies, making A, C and D only the correct answer.