Which system of equations can be used to solve the following problem?
each child ticket for a ride costs 2$ , while each adult ticket costs 6$ . if the ride collected a total of 148$ , and 38 tickets were sold , how many of each type of ticket were sold? let c be the number of child tickets and a be the number of adult tickets.

a. 2a+6c=38
a+c=148

b. 2c+6a=38
a+c=148

c. 2c+6a=148
a+c=38

d. 6c+2a=148
c+a=38