Dyslexia is a reading disorder that involves difficulty in reading, spelling, and decoding words despite having normal intelligence. It primarily affects reading and language processing, making it a reading disability. It is not related to writing or arithmetic disabilities.
Step 1: Analyze the options.
(A) Writing disability: While people with dyslexia may struggle with writing due to related difficulties in reading and language processing, dyslexia specifically refers to a reading disability.
(B) Reading disability: This is the correct answer. Dyslexia is a reading disability that impacts the ability to read and understand written language.
(C) Arithmetic disability: Dyslexia is not associated with arithmetic disabilities; it is a specific learning disorder related to reading.
(D) Mental disability: Dyslexia is not a mental disability but a neurodevelopmental disorder affecting reading abilities.
Step 2: Conclusion.
The correct answer is (B), as dyslexia is a reading disability that specifically impacts reading skills.
Final Answer:
\[
\boxed{(B) \, \text{Reading disability}}
\]