Electromagnetic spectrum — practice question

As shown, two beams of radiation, P and S, pass into an electric field. What types of radiation are P and S?

• AP: beta ($\beta$), S: alpha ($\alpha$)
• BP: beta ($\beta$), S: gamma ($\gamma$)
• CP: gamma ($\gamma$), S: alpha ($\alpha$)
• DP: gamma ($\gamma$), S: gamma ($\gamma$)