Answer:
Option B.
Explanation:
Given information:
.
According to the angle sum property of a triangles, the sum of interior angles of a triangle is 180°.
Apply angle sum property on triangle AEJ.
![\angle A+\angle E+\angle J=180^(\circ)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/whi3b0s1ctrmq2qoc4jf8aip1dind5j3gs.png)
![48^(\circ)+90^(\circ)+\angle J=180^(\circ)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/d9ee9o52j7v746yt93iiyn1x8vae84pf22.png)
![138^(\circ)+\angle J=180^(\circ)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/8i2tidz4okwdacca2nxn95hsfcfgcp9wfk.png)
Subtract 138 from both sides.
![\angle J=180^(\circ)-138^(\circ)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/ec0j0zrd8l3ccceg9rbsyl6joco2pcygax.png)
![\angle J=42^(\circ)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/b123p6cfplqiikguxiu4p4o0n57z03h5ry.png)
The measure of angle J is 42°.
According to exterior angle property, the sum of two interior angles of a triangle is equal to the third exterior angle.
Apply exterior angle property on triangle JMS.
![\angle EJA+\angle JSM=\angle EMS](https://img.qammunity.org/2020/formulas/mathematics/middle-school/g8xzys9618qjzmzksm8he3xufi58e0q9ar.png)
![42^(\circ)+\angle JSM=59^(\circ)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/qcwyb8pwszxmiv34oq5woa9oopdlmfqpe9.png)
Subtract 42 from both sides.
![\angle JSM=59^(\circ)-42^(\circ)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/ci09c6td87o6d229ebtpcbk9e4wsily1nd.png)
![\angle JSM=17^(\circ)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/1ugkb6ghqryj4wz4vmmcpiam6buigjjs7w.png)
The measure of ∠JSM is 17°.
Therefore, the correct option is B.