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Answer: (b) and (c) are true, (a) is not ($3^{10}$ is odd and square)

$3^{10}=3\times3\times3 ...\times3$ product of odd numbers $\therefore$ odd (and not even)
$\therefore$ (a) is not true but (b) is

$3^{10} = \left( 3^5 \right)^2$, so it is also a perfect square $\therefore$ (c) is true
(because $3^{10}=\underbrace{3\times3\times...\times3}_{\text{10 times}} = \underbrace{3\times3\times...\times3}_{\text{5 times}}\times\underbrace{3\times3\times...\times3}_{\text{5 times}} = \left(3^5\right)\times\left(3^5\right)$)



 


This problem is taken from the UKMT Mathematical Challenges.
You can find more short problems, arranged by curriculum topic, in our short problems collection.