LCM of Rational Numbers The least common multiple (LCM) of a set of numbers A is the smallest integer b such that b/a is an integer for all integers a in A. This definition can be extended to rational numbers!
Task
Find the smallest positive rational b such that b/a is an integer for all rationals a in the input.
Rules

Standard loopholes are forbidden.
You may take numerators and denominators separately in the input, but may not take doubles, floats, etc.
The input may not be fully reduced.
You may take integer inputs as rationals with denominator of 1.
Submissions that would feed rational numbers to an LCM/GCD builtin are allowed, but non-competing.

Test Cases
In:  3
Out: 3

In:  1/17
Out: 1/17

In:  1/2, 3/4
Out: 3/2

In:  1/3, 2/8
Out: 1

In:  1/4, 3
Out: 3

In:  2/5, 3
Out: 6

In:  1/2, 3/4, 5/6, 7/8
Out: 105/2

This is code-golf, so submissions using the fewest bytes win!
J, 3 bytes, non-competing.

*./


Given a list of rational inputs, this folds LCM through it.