Which pair of the following belongs to Basidiomycetes?

$A$ telescope has an objective lens of focal length $200 \ cm$ and an eyepiece with focal length $2 \ cm$. If this telescope is used to see a $50 \ m$ tall building at a distance of $2 \ km$,what is the height of the image of the building formed by the objective lens in $cm$?

An atomic power nuclear reactor can deliver $300\, MW$. The energy released due to fission of each nucleus of a uranium atom ${U^{238}}$ is $170\, MeV$. The number of uranium atoms fissioned per hour will be

If $P=(0,1,2)$,$Q=(4,-2,1)$,and $O=(0,0,0)$,then $\angle POQ$ is equal to

Which is the best method to obtain virus-free plants through tissue culture?

Box $A$ contains $2$ black and $3$ red balls, while Box $B$ contains $3$ black and $4$ red balls. Out of these two boxes, one is selected at random; and the probability of choosing Box $A$ is double that of Box $B$. If a red ball is drawn from the selected box, then the probability that it has come from Box $B$ is: