How many secondary hydroxyl groups are present in glucose?

Which of the following compounds will show mutarotation?

For 'invert sugar',the correct statement$(s)$ is(are)
(Given: specific rotations of $(+)$-sucrose,$(+)$-maltose,$L-(-)$-glucose and $(+)$-fructose in aqueous solution are $+66^{\circ}, +140^{\circ}, -52^{\circ}$ and $+92^{\circ}$,respectively)
$(A)$ 'invert sugar' is prepared by acid catalyzed hydrolysis of maltose
$(B)$ 'invert sugar' is an equimolar mixture of $D-(+)$-glucose and $D-(-)$-fructose
$(C)$ specific rotation of 'invert sugar' is $-20^{\circ}$
$(D)$ on reaction with $Br_2$ water,'invert sugar' forms saccharic acid as one of the products

Which of the following is not possible in glucose?

Which of the following is the correct structure of adenosine?

Which of the following statements about ribose is incorrect?