In the following spelling question, out of the four given alternatives, select the word that is correctly spelt and commonly used in English.

Introduction / Context:
This question assesses your ability to recognise a correctly spelt English word among several incorrect spellings. Spelling questions often include one correct standard word and three distractors that look similar but have extra letters, missing letters, or incorrect combinations. Here, the correctly spelt word is a somewhat advanced vocabulary term that appears in literature and formal writing.

Given Data / Assumptions:

• Four options are given, but only one is correct.
• The options resemble real words but contain likely errors.
• The exam may draw words from literary or descriptive English.
• The correct option must match dictionary spelling.

Concept / Approach:
"Pulchritude" is a formal noun in English meaning physical beauty or attractiveness. It is uncommon in everyday conversation but is a well known word in advanced vocabulary lists and examinations. The other words in the options list either are not standard English or are incorrectly formed. Recognising prefixes, suffixes, and common patterns in English helps to eliminate wrong options even when the correct word is rare.

Step-by-Step Solution:
Step 1: Examine each option and check whether it resembles any known English word. Step 2: "Tidlers" seems related to "tiddlers", a word for small fish or children, but the exact spelling is not standard here. Step 3: "Thistlees" looks like a mistaken attempt at "thistles"; the double "e" is unnecessary. Step 4: "Tenderred" suggests "tendered" or "tender", but the double "r" is incorrect in this position. Step 5: "Pulchritude" is recognised as a correct word meaning beauty, and the spelling matches standard dictionaries.

Verification / Alternative check:
To verify, recall that "pulchritude" is often used in contexts such as "a woman of great pulchritude" or "the pulchritude of the natural landscape". Dictionaries confirm both the spelling and meaning. The other three items do not appear in formal dictionaries with those exact spellings, making them unreliable choices in a competitive exam context.

Why Other Options Are Wrong:
Option a: "tidlers" is not a standard spelling for any common English word; the more familiar form is "tiddlers". Option b: "thistlees" adds an unnecessary "e" and does not match the correct plural "thistles". Option d: "tenderred" has an extra "r" and does not represent the correct past tense "tendered".

Common Pitfalls:
Students are sometimes tempted to avoid unusual looking words and pick the most familiar ones, even if they are misspelt. However, exams often include advanced vocabulary precisely to reward students who read widely. It is a good habit to build a vocabulary notebook and regularly review new words and their correct spellings. This strategy will help in both spelling and usage based questions.

Final Answer:
The correctly spelt word is pulchritude.