To determine which statements about Sir Syed Ahmed Khan are true, let's analyze each statement with historical context:

1. Statement A: "Syed Ahmed Khan was in judicial service of the British Government."
   • This statement is correct. Sir Syed Ahmad Khan began his career as a jurist in the service of the British East India Company and later the British Government.
2. Statement B: "He was Member of imperial Legislative Council in 1878."
   • This statement is correct. Sir Syed was nominated to the Imperial Legislative Council by the Viceroy in 1878.
3. Statement C: "He earned Knighthood in 1888."
   • This statement is correct. He was knighted by the British in 1888 for his services to education and society.
4. Statement D: "He opposed western scientific education."
   • This statement is incorrect. In fact, Sir Syed Ahmed Khan was a strong proponent of modern scientific education. He founded the Muhammadan Anglo-Oriental College (later Aligarh Muslim University) to promote Western-style education among Muslims.
5. Statement E: "He said that religion should not be altered."
   • This statement is somewhat misleading. Although Sir Syed advocated for rational interpretation of religious texts, he did not fundamentally oppose religion or its teachings. His emphasis was more on adapting religious practices to align with modern times.

Based on the analysis above, the correct answer is the option A, B, C Only, as statements A, B, and C about Sir Syed Ahmed Khan are true.