Solution containing 23 g $HCOOH$ is/are :

(A) $46gof70\%\left(\frac{w}{V}\right)HCOOH(d_{solution}=1.40g/mL)$

 $70\%\frac{w}{V}HCOOH\underset{ }{\overset{ }{\to }}70gHCOOH$  in 100 mL solution.
Mass of solution  $=1.4\times 100=140g$
So, in 140g solution , mass of $HCOOH=70g$ in 46 g, mass of  $HCOOH=\frac{70}{140}\times 46=23g$

(B)  $100MHCOOH\stackrel{ }{\to }10moleHCOOHin$  1000 ML solution mass of solution  $=1000g$

Mass of $HCOOH=10\times 46=460g$
So in 50 g solution mass of  $HCOOH=\frac{460}{1000}\times 50=23g$

(C)  $25\%\frac{W}{W}HCOOH\stackrel{ }{\to }25gHCOOHin100g$  solution

So in  50 g solution, mass of  $HCOOH=12.5g$