If two tangents drawn from a point P to the parabola `y^2=4x` are at right angles, then the locus of P is `(a) `2x+1=0` (b) `x=-1` (c) `2x-1=0` (d) `x=1`

Explanation

To solve the problem, we need to find the locus of the point \( P \) from which two tangents are drawn to the parabola \( y^2 = 4x \) such that these tangents are at right angles to each other.

### Step-by-Step Solution:

1. **Identify the Parabola and its Properties:**
The given parabola is \( y^2 = 4x \). This parabola opens to the right and has its vertex at the origin \( (0, 0) \). The parameter \( a \) (the distance from the vertex to the focus) is \( 1 \) since \( 4a = 4 \).

2. **Find the Directrix of the Parabola:**
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