In this one-word substitution question, choose the single English word that best expresses the phrase "evening prayer in church", referring to a Christian service or set of prayers held in the evening.

Introduction / Context:
This question tests your familiarity with a term used in Christian liturgical practice and in literature. Many classic novels and historical texts refer to different services during the day, and knowing the specific names of these services can be helpful in understanding context. The phrase in the stem asks for the name of the evening prayer service in a church setting.

Given Data / Assumptions:
The phrase is "evening prayer in church". We must select the one-word term for that religious service. We assume standard Christian liturgical vocabulary in English.

Concept / Approach:
The correct term is "vespers". In many Christian traditions, vespers is the service of evening prayer, typically held around sunset or early evening. It forms part of the daily cycle of canonical hours, which also includes services like matins and lauds. The other options refer to unrelated objects or types of dance, so they clearly do not fit the religious context of the question.

Step-by-Step Solution:
Step 1: Recognise that the phrase is about a religious ceremony, not an object or dance. Step 2: Recall that "vespers" denotes the evening prayer service in many churches. Step 3: Check each option: "sheath" is a cover, "jig" and "waltz" are dances, leaving "vespers" as the only suitable term. Step 4: Match the meaning of "vespers" with "evening prayer in church". Step 5: Choose Option D as the correct one-word substitution.

Verification / Alternative check:
To verify, consider a sentence such as "The bells rang out for vespers" or "The monks gathered for vespers at dusk". In each case, "vespers" clearly refers to an evening church service. Replacing "vespers" with "waltz" or "sheath" would destroy the intended meaning. This confirms that "vespers" is the only option that fits the phrase provided in the question.

Why Other Options Are Wrong:
Option A, "Sheath", is a cover for a blade, tool, or cable, and has no religious connotation. Option B, "Jig", is a lively dance, often associated with folk traditions. Option C, "Waltz", is a ballroom dance in triple time. Since the stem clearly speaks of prayer in a church, not dancing or tool covers, these options are irrelevant and incorrect here.

Common Pitfalls:
Some candidates may be unfamiliar with church-related vocabulary and might guess randomly among the options. Others might be tempted by the musical sound of "waltz" or "jig" without noticing the religious context. To avoid such mistakes, always pay attention to domain clues in the stem: words like "prayer", "church", "service", or "mass" signal that the answer should belong to religious terminology rather than everyday objects or dances.

Final Answer:
The correct answer is "Vespers".