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Let A and B denote the statements A : ...

Let `A and B` denote the statements
`A : cos alpha + cos beta + cos gamma =0`
`B : sin alpha + sin beta + sin gamma = 0`
If `cos(beta - gamma) + cos (gamma -alpha) + cos (alpha -beta) = - (3)/(2)`,
then

A

A is false and B is true

B

both A and B are true

C

both A and B are false

D

A is true and B is false.

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