First Principles Thinking: income tax expense = taxes payable + change in deferred tax liability
B is correct. Per the CFA Curriculum, income tax expense = income taxes payable + change in deferred tax liability. Taxes payable = GBP 3,843 × 30% = GBP 1,153; increase in DTL = GBP 257; income tax expense = GBP 1,153 + GBP 257 = GBP 1,410. Note this equals GBP 4,700 × 30%, confirming tax expense is 30% of accounting profit.
A (GBP 1,153) captures only the taxes payable component, omitting the GBP 257 increase in the deferred tax liability, which the CFA Curriculum requires to be added.
C (GBP 4,584) is the income tax expense for Year 2, not Year 1.