If $a, b, c, d$ are positive real numbers such that $a + b + c + d = 2$,then $M = (a + b)(c + d)$ satisfies the relation:

  • A
    $0 < M \le 1$
  • B
    $1 \le M \le 2$
  • C
    $2 \le M \le 3$
  • D
    $3 \le M \le 4$

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Let $R^2$ denote $R \times R$. Let $S = \{(a, b, c) : a, b, c \in R \text{ and } ax^2 + 2bxy + cy^2 > 0 \text{ for all } (x, y) \in R^2 - \{(0, 0)\}\}$. Then which of the following statements is (are) $TRUE$?
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$(B) \text{If } (3, b, \frac{1}{12}) \in S, \text{ then } |2b| < 1$
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