Let the pizza have $60$ slices, since the least common multiple of $(5,3,4)=60$.  Therefore, Alex ate $\frac{1}{5}\times60=12$ slices, Beth ate $\frac{1}{3}\times60=20$ slices, and Cyril ate $\frac{1}{4}\times60=15$ slices.  Dan must have eaten $60-(12+20+15)=13$ slices.  In decreasing order, we see the answer is $\boxed{\textbf{(C) }\text{Beth, Cyril, Dan, Alex}}$.
Four siblings ordered an extra large pizza. Alex ate $\frac15$, Beth $\frac13$, and Cyril $\frac14$ of the pizza. Dan got the leftovers. What is the sequence of the siblings in decreasing order of the part of pizza they consumed?
$\textbf{(A) } \text{Alex, Beth, Cyril, Dan}$ 
$\textbf{(B) } \text{Beth, Cyril, Alex, Dan}$ 
$\textbf{(C) } \text{Beth, Cyril, Dan, Alex}$ 
$\textbf{(D) } \text{Beth, Dan, Cyril, Alex}$ 
$\textbf{(E) } \text{Dan, Beth, Cyril, Alex}$