Answer: C
\((\sin\theta + \cos\theta)^2\) \(= \sin^2\theta + \cos^2\theta + 2\sin\theta \cos\theta\) \(= 1 + 2 \times \frac{1}{2}\) \([\, \because \sin\theta \cos\theta = \frac{1}{2}]\) \(= 1 + 1\) \(= 2\)
\((\sin\theta + \cos\theta)^2\) \(= \sin^2\theta + \cos^2\theta + 2\sin\theta \cos\theta\) \(= 1 + 2 \times \frac{1}{2}\) \([\, \because \sin\theta \cos\theta = \frac{1}{2}]\) \(= 1 + 1\) \(= 2\)