Which poet's work is characterized by mental illness and personal trauma?

The correct choice is Sylvia Plath, whose poetry is deeply rooted in her personal experiences, including mental illness and trauma. Plath's life was marked by struggles with depression, and these themes are vividly reflected in her work.

Her collection "Ariel," for example, explores intense emotions, existential despair, and the complexities of identity, often using stark imagery and confessional style to articulate her inner turmoil. Plath's writing not only illustrates her mental health challenges but also encapsulates the broader themes of alienation and suffering, making her work resonate with the experiences of many who have faced similar struggles.

This focus on personal trauma and psychological complexity sets Plath apart from the other poets listed. While Robert Frost, Anna Akhmatova, and W.B. Yeats certainly engaged with profound themes in their poetry, their works do not center as explicitly on the interplay of mental illness and personal trauma as Plath's does.