" 28."sqrt(10)times sqrt(15)" is equal to "

sqrt(10).sqrt(15) is equal to

sqrt(10).sqrt(15) is equal to

sqrt(10)xx sqrt(15)

Find sqrt(iota) times sqrt(-iota) is equal to

sqrt10xxsqrt15 is equal to

sqrt(10+2sqrt(6)+2sqrt(10)+2sqrt(15)) is equal to (sqrt(2)+sqrt(3)+sqrt(5))(sqrt(2)+sqrt(3)-sqrt(5))(c)(sqrt(2)+sqrt(5)-sqrt(3))(d) None of these