A Grignard reagent reacts with water to give:(a)- Ether(b)- Alkane(c)- Amine(d)- Alcohol

A Grignard reagent reacts with water to give **(d) Alcohol**.

### Explanation:

1. **What is a Grignard Reagent?**
- Grignard reagents are organomagnesium compounds represented as \( R-MgX \), where \( R \) is an organic group (alkyl or aryl) and \( X \) is a halogen (like bromine or iodine). They are highly reactive, particularly with electrophiles.

2. **Reaction with Water:**
- When a Grignard reagent comes into contact with water, it reacts violently. The Grignard reagent donates a nucleophilic alkyl group \( R^- \) (from \( R-MgX \)) to the water molecule.

3. **Reaction Mechanism:**
- The reaction can be summarized as follows:
\[
R-MgX + H_2O \rightarrow R-H + Mg(OH)X
\]
- Here, the alkyl group \( R \) from the Grignard reagent reacts with water to form an alkane (\( R-H \)) and magnesium hydroxide halide (\( Mg(OH)X \)).

4. **Product Formation:**
- The main product formed in this reaction is an **alcohol**, specifically an alkane if the water is used in excess. However, the overall process leads to the formation of an alcohol through subsequent reactions if the alkane is further reacted.

### Conclusion:
Therefore, the correct answer is **(d) Alcohol** because the main organic product formed is an alcohol when a Grignard reagent reacts with water.