The first multiples of 4 and 10 are given below
[tex]\begin{gathered} 4\to4,8,12,16,20,24,28,32,36,40 \\ 10\to10,20,30,40 \end{gathered}[/tex]
Therefore, the common denominators of 1/4 and 7/10 are the intersection of the two lists above; this is,
[tex]\text{common denominators}\to\mleft\lbrace20,40\mright\rbrace[/tex]
Thus, the answers are options B and E
