Step 1: Understanding Lord Ram's exile.
According to the Ramayana, Lord Ram spent his first night in exile near the banks of the Sarayu River.
Step 2: Analyzing the options.
- (A) Ganga River: Lord Ram did not spend his first night by the Ganga River during his exile.
- (B) Sarayu River: This is the correct answer, as Lord Ram spent his first night at the Sarayu River.
- (C) Tamsa River: The Tamsa River is not where Lord Ram spent his first night in exile.
- (D) Subarnarekha River: This river is not connected to Lord Ram's exile.
Step 3: Conclusion.
The correct answer is (B) Sarayu River.