In the following spelling question, out of the four alternatives, select the word that is correctly spelt in standard English.

Introduction / Context:
This question focuses on spelling in English, particularly on recognising a correctly spelt word among several incorrect options. Accurate spelling is important in written communication, examinations, and professional contexts. Here, three of the words are misspelt or non standard, and only one is an accepted spelling in standard English, especially in British usage, which many competitive exams follow.

Given Data / Assumptions:

• Four words are provided, but only one is correct.
• The exam most likely follows British spelling conventions.
• The word parts "amphybia", "indanted", and "ancumber" resemble real words but are distorted.
• "Levelled" is a common English word related to "level".

Concept / Approach:
To solve spelling questions, you should look for familiar roots and patterns and compare them to standard usage. The forms "amphybia", "indanted", and "ancumber" seem to be incorrect attempts at "amphibia" or "amphibian", "indented" or "intended", and "encumber". In contrast, "levelled" is the correct past tense and past participle of "level" in British English, where double consonants are often used before adding "ed" or "ing" to a stressed syllable.

Step-by-Step Solution:
Step 1: Carefully read each option and see if it matches any known English word. Step 2: Recognise that "amphybia" is probably intended to look like "amphibia", but the "y" is incorrect and the whole form is not standard. Step 3: Notice that "indanted" does not correspond to a common English word and seems wrongly formed. Step 4: Observe that "ancumber" is likely a distorted form of "encumber". Step 5: Confirm that "levelled" is a correct spelling, especially in British English, for the verb "to level" in its past tense.

Verification / Alternative check:
You can verify "levelled" by recalling phrases like "The ground was levelled before construction" or "They levelled the playing field." Dictionaries that use British spelling list "levelled" and "levelling" with double "l". American English sometimes uses "leveled", but exams that focus on general English often accept or prefer the British forms. The other three options do not appear as standard words in recognised dictionaries.

Why Other Options Are Wrong:
Option a: "amphybia" is incorrect; the accurate biological term is "amphibia" or "amphibian". Option b: "indanted" does not correspond to any common English word and has no clear meaning. Option c: "ancumber" is incorrect; the proper verb is "encumber", meaning to burden.

Common Pitfalls:
A frequent mistake is being misled by unfamiliar but complex looking spellings. Candidates may assume that the longest or most unusual looking word is correct. Another pitfall is forgetting the difference between British and American spellings. To avoid errors, constantly read good quality English texts and pay attention to how common verbs and nouns are spelt in context.

Final Answer:
The correctly spelt word is levelled.