Select the word with the correct spelling from the options given.

Introduction / Context:
This item checks spelling recognition, a core part of English vocabulary skills. Candidates are asked to identify the correctly spelled word out of four options. Such questions ensure that learners are familiar not only with basic words but also with slightly technical or academic vocabulary. The word schemata is the plural of schema and is widely used in fields like psychology, linguistics, and philosophy.

Given Data / Assumptions:

• Options: deseased, spedier, schemata, unioniest.
• Exactly one option is correctly spelled in standard English.
• The other three are either misspellings or non standard forms.
• The task is to visually recognise the authentic form, possibly from prior reading experience.

Concept / Approach:
The best way to approach spelling questions is to mentally compare each option with what you have seen in reliable texts or dictionaries. Deseased seems intended to represent diseased, which is spelled with i rather than e after d. Spedier appears to be a misspelling of speedier, which has a double e. Unioniest looks like a confused attempt at unionist or unionised. Only schemata exactly matches a known plural form of schema. The suffix mata is part of the original Greek pattern and is preserved in English technical usage, making schemata correct.

Step-by-Step Solution:
Step 1: Look at option a, deseased. Think of the common adjective that describes someone with a disease; it is diseased, not deseased. Step 2: Look at option b, spedier. The comparative of speedy is speedier with double e, so spedier is incorrect. Step 3: Look at option c, schemata. This is a recognised plural form of schema, used in academic writing, and appears correctly spelled. Step 4: Look at option d, unioniest. There is no standard English word with this exact spelling; the related term would be unionist. Step 5: Confirm that schemata is the only word that matches a standard form in dictionaries.

Verification / Alternative check:
If you have read material in psychology or cognitive science, you may have seen sentences like Mental schemata influence perception. Checking that memory shows that schemata is indeed used and spelt in this way. On the other hand, normal spelling rules give diseased, speedier, and unionist, not the forms present in options a, b, and d. This serves as a strong internal verification that schemata is correct.

Why Other Options Are Wrong:
deseased: Incorrect; the correct form is diseased, with i after d, and without an extra e after s.
spedier: Incorrect comparative of speedy; the correct form is speedier with double e.
unioniest: Not a standard word; the intended related word is unionist.

Common Pitfalls:
Students may hesitate to choose schemata because it looks less familiar and more technical than the other options. However, exams often intentionally use specialised but correctly spelled words among familiar but misspelled options. The key is to trust rules and prior reading experience. Building exposure by reading across different subjects, including science and humanities, makes it easier to recognise such technical vocabulary under exam pressure.

Final Answer:
The correctly spelled word is schemata, so option c is correct.