Fixes tsc errors

package.json

@@ -81,6 +81,6 @@
     "ts-loader": "^6.0.4",
     "ts-node": "^8.3.0",
     "tslint": "^5.18.0",
-    "typescript": "^3.5.2"
+    "typescript": "^3.5.3"
   }
 }

src/interfaces/answeroptions/IAnswerEntity.ts

+import { AnswerType } from '../../enums/AnswerType';
 import { IValidationStackTrace } from '../IValidationStackTrace';
 
 export interface IAnswerBase {
-  readonly TYPE: string;
+  readonly TYPE: AnswerType;
   isCorrect: boolean;
   answerText: string;
 }