The two families are:
Hendersons: Robert, Mary, Tommy, Don, William
Penicks: Jerome, Ellen, Kate, Susan
There are 3 canoes, 3 people in each, total 9 people.
Given:
- The two mothers (Mary and Ellen) ride in the same canoe.
- The three brothers (Tommy, Don, William) each ride in separate canoes.
Let’s analyze:
Canoe 1: Mary, Ellen, X
→ This canoe already has 2 females. To satisfy the "at least one person from each family" rule, X must be someone from Hendersons (if Ellen is Penick), so perhaps Kate or Susan.
That makes Canoe 1: Mary, Ellen, Kate/Susan (All females) ✓
Canoe 2: Tommy, ?, ?
Canoe 3: Don, ?, ?
Canoe 4: William, ?, ?
Each brother must ride separately. That leaves only 4 more people to fill the other two canoes: Robert, Jerome, Kate, Susan.
So:
- One canoe will be Tommy + Robert + Susan
- Another will be Don + Jerome + Kate
- Third will be Mary + Ellen + the remaining girl
But crucially, the canoe with Mary and Ellen must be all female (Mary, Ellen, one of the daughters). So:
\[
\boxed{\text{(B) One of the canoes has only females in it}}
\]