English grammar error-spotting (article and collocation with ‘‘deadline’’): Identify the erroneous part among A–D; select ‘‘No error’’ only if all parts are correct. Pay attention to the noun phrase after the preposition: ‘‘The ability to plan, / organise and coordinate work is all fundamental / to working within deadline. / No error.’

Given data

• C: ‘‘to working within deadline.’’

Concept / Approach
Countable singular nouns like ‘‘deadline’’ normally require an article or determiner. The idiomatic expression is ‘‘within the deadline’’ (specific) or ‘‘within deadlines’’ (general). Thus the error lies in the missing article/determiner.

Step-by-step correction
Replace C → ‘‘to working within the deadline.’’Alternative (generic practice): ‘‘… within deadlines.’’

Verification
With the article, the prepositional phrase is complete and idiomatic: ‘‘within the deadline’’ = within the stipulated time limit.

Common pitfalls

• Dropping articles before singular countable nouns (deadline, target, budget).

Final Answer
to working within deadline.